First time poster...Does any use UV Sterilizers as part of their filtration system?

[tkki1230]

I have a 650 gallon Fish tub that I will be using to power a couple of 4x8 growbeds. It currently has a Settling tank, Bio filtration, and a 35w UV Sterilizer. Can I still use the UV? There are some local "experts" that are telling me that the UV will render my Aquaponics system useless. This seems rather far fetched and illogical. There must be a lot of people out there running UV in their systems. Can I still use mine?

[fishfood]

What they tell you is correct uv kills the good bacteria

[GaryD]

Hi Tkki1230,

Since we're talking about logic, if we are relying on nitrifying bacteria to maintain water quality, why would we want to kill them?

In reality, there are very few people that I know of that use UV sterilisers.....not so much because they will render your system useless, but because there is no point.

Aquaponics is an eco-system (see here (http://www.microponics.net.au/?p=142) for a more complete explanation of this statement) and it follows that eventually all of the organisms will manage their niche and the system will be in balance.

Your settling tank and bio-filter will serve you much better in stabilising an AP system than a UV steriliser.

Gary

[tkki1230]

Hi Tkki1230,

Since we're talking about logic, if we are relying on nitrifying bacteria to maintain water quality, why would we want to kill them?

In reality, there are very few people that I know of that use UV sterilisers.....not so much because they will render your system useless, but because there is no point.

Aquaponics is an eco-system (see here (http://www.microponics.net.au/?p=142) for a more complete explanation of this statement) and it follows that eventually all of the organisms will manage their niche and the system will be in balance.

Your settling tank and bio-filter will serve you much better in stabilising an AP system than a UV steriliser.

Gary

I always thought that most of the beneficial bacteria resided in the filter media where it couldn't be touched by the UV. Why do all of the Pond people use sterilizers other than getting rid of Algae? Wouldn't their systems crash if the UV killed off all of the good bacteria? I'm really confused.

Thanks for all of your replies!!

[Crusty]

I always thought that most of the beneficial bacteria resided in the filter media where it couldn't be touched by the UV. Why do all of the Pond people use sterilizers other than getting rid of Algae? Wouldn't their systems crash if the UV killed off all of the good bacteria? I'm really confused.

Thanks for all of your replies!!

Hi tkki. I dont see any issue with it.

[tkki1230]

Hi tkki. I dont see any issue with it.

Thanks for your original post. That was extremely educational, and very much along the lines that I was thinking.

[Crusty]

Thanks for your original post. That was extremely educational, and very much along the lines that I was thinking.

I am glad you got to read it and it was helpful. I went to edit it and the forum logged me out or some other glitch and removed post.

[GaryD]

Hi Crusty,

Welcome back.......long time no see/hear.

I get the impression that there's a post missing. If you were simply editing, and you got timed out before you saved the newer version, we should have been left with the original version anyway.

I've experienced a several situations (since upgrading the forum software), where I'm sure I hit the Save button but the post has disappeared. I dismissed it as having maybe hit the Preview button instead........now you've got me wondering.

Can you post something similar to your original post......for the benefit of those of us who didn't get to see it?

Gary

[Crusty]

Hi Crusty,

Welcome back.......long time no see/hear.

I get the impression that there's a post missing. If you were simply editing, and you got timed out before you saved the newer version, we should have been left with the original version anyway.

I've experienced a several situations (since upgrading the forum software), where I'm sure I hit the Save button but the post has disappeared. I dismissed it as having maybe hit the Preview button instead........now you've got me wondering.

Can you post something similar to your original post......for the benefit of those of us who didn't get to see it?

Gary

Hi Gary

I think the issue lays in the session time out in the admin general settings...

Normally, I write posts in word, copy and paste for this reason. However, I was lazy this time round.

The original post went on for some time about the pros and cons of UV in aquaculture, hydroponics and its relevant use or application in integration, like aquaponics. From personal and professional experience there is no issue with the use of UV clarifiers in aquaponics but it is a matter of personal choice based on the system design.

[tkki1230]

The post that got zapped was rather impressive. I would've kept it for myself if I'd known it was going to disappear. I'd never read anything like it before, and I'm not one to exaggerate.

[GaryD]

Hi,


From personal and professional experience there is no issue with the use of UV clarifiers in aquaponics but it is a matter of personal choice based on the system design.
I agree in principle, however, there's a difference between the approaches used in aquaculture and aquaponics.

In aquaculture, efforts will be made to suppress most organisms in an attempt to limit any damage posed by harmful ones. Similarly, in a hydroponics system, the components may be sterilised at regular intervals. Neither environment could be described as an eco-system.

In aquaponics (which is an eco-system), very little will be done to suppress any organism in the belief that all organisms will eventually occupy their own niche in harmony with others......once the system achieves a state of balance.

I guess if it does no harm.......but achieves little that is useful......what's the point?

Gary

[Crusty]

Hi,


I agree in principle, however, there's a difference between the approaches used in aquaculture and aquaponics.

In aquaculture, efforts will be made to suppress most organisms in an attempt to limit any damage posed by harmful ones. Similarly, in a hydroponics system, the components may be sterilised at regular intervals. Neither environment could be described as an eco-system.

In aquaponics (which is an eco-system), very little will be done to suppress any organism in the belief that all organisms will eventually occupy their own niche in harmony with others......once the system achieves a state of balance.

I guess if it does no harm.......but achieves little that is useful......what's the point?

Gary

I would suppose UV clarifiers achieve what they are intended for, to prevent algae. One of the organisms that plant growers do not want inhibiting growth. As I said it is a matter of choice in system design to which I have seen the results. The OP asked if they could use their 35watt UV, which does nothing more than alter the DNA of algae to inhibit its growth, answers offered clearly said it can not be done. I was simply pointing out that it can be with no detriment to the system as the UV mentioned does not have an effect, good or bad, on bacteria. Which was not the advice offered the OP.

Eco-system? At some point, usually every day we interfere the organisms.

[GaryD]

I would suppose UV clarifiers achieve what they are intended for, to prevent algae.
OK.....I wasn't coming at the problem from that perspective.

Algae is a problem that impacts most aquaponicists sooner or later and it's the product of nutrients in the presence of sunlight. I deal with it by covering my fish tanks so that algae can't grow.....but I can see how a UV steriliser would be useful if you didn't have that option.


Eco-system? At some point, usually every day we interfere the organisms.
I agree......but to much less of an extent in aquaponics than with commercial aquaculture or hydroponics.

Gary

[tkki1230]

I found the missing post in my Outlook archives. Here it is-



Contrary to the replies here, sorry Gents, there is no issue with using UV at those levels in your system at all.

The ups are that it will kill off many pathogen, bacteria or fungus that are deteramental to both the fish and the plants along with algae. (UV is also used in hydroponics for sterilizing nutrient solution) The down sides are, you can overdose (o3) and it can damage the cell structure of the plants though in the small amount you are using this will not happen especially if there is sufficient distance between the UV unit and the grow bed. The other downside to keep in mind that UV can cause micronutrients to precipitate out of the water leaving your plants short of Boron, Manganese and Iron. Again, keep in mind this is when UV doses are a great deal higher than simple clarifiers.

You are correct that the bacteria live in your biofilter media, as logic suggests and are protected from the UV. It is important as to where you actually install the clarifier though. The bacteria that are in the actual water column are of little consequence to the overall performance of the nitrification process and quite often they will be heterotrophs (nasty oxygen eaters) in suspension, which you will be happy to kill if you can. UV at much higher doses is often used in commercial aquaculture and all of them use bio filters as a point of logic.

A 35watt UV unit will only be operating as a clarifier and very much a bit of over kill for your system volume. More suited to 15000 or more liters of water but for the cost of $40 a year to run it is not an issue. However, there is the additional cost of the bulbs, which have an effective life span of about 9000hours (just over a year) at a cost of about $80 each. Running the bulbs for longer than the manufacturer suggests is really a waste of electricity and money. Introducing a timer to run during the day to reduce the cost and extend the life may be of help. Just the same, your UV clarifier (often incorrectly termed as a sterilizer) will prevent any algae problems. And really, who wants algae in their system sucking up the plant nutrient, causing pH fluctuations, Do2 issues and using up valuable room on your filter media.

Once you have algae, you have algae and have to chemically treat it to remove it, which can be quite toxic. This is important for the installation of UV. If you already have algae the UV clarifier will do very little to rid you of it and will only have some minor control over new growth. Meaning you would have to treat with a copper sulphate solution or some other algicide before the use of UV. (yuck)


---Quote---
Tip for the purist: The application of barley straw within your system can be introduced as a control method for algae, as it produces hydrogen peroxide as it breaks down and hydrogen peroxide inhibits the growth of algae and helps oxygenate your water. Happy days!
---End Quote---


A matter of choice really. Do you need one to grow plants? Not at all. Will it harm your system balance? Not at all though the opposite is true. Would you use one without solids removal? No, too many particles in suspension which render the UV redundant. When thinking if there is a point to using them, keep in mind that micro algae is not easily seen, unless in bloom and will be present throughout any system maintaining nitrogen (specifically nitrate nitrogen) at levels consistent with good plant growth and have grow beds sitting in the sun.

[Crusty]

OK.....I wasn't coming at the problem from that perspective.

Algae is a problem that impacts most aquaponicists sooner or later and it's the product of nutrients in the presence of sunlight. I deal with it by covering my fish tanks so that algae can't grow.....but I can see how a UV steriliser would be useful if you didn't have that option.


I agree......but to much less of an extent in aquaponics than with commercial aquaculture or hydroponics.

Gary

It is a greater problem that happens a lot sooner than one would think. Covering a fish tank will have no effect at all in the prevention of algae if your grow beds are in any form of sunlight, which they will be unless you are growing mushrooms.

Covering a fish tank can have a detrimental effect on temperature in summer and it will negatively effect gas exchange with in the tank and the fish will suffer without a doubt. Further issues with covering tanks that contain your fish, are the constant light changes when you open it to feed or observe or for any other reason. These light changes will spook your fish, which in turn will have them displaying odd behavior that will sometimes be mistaken for agressive feeding when in fact they are swimming irregularly and are frightened. Let's not forget the stress sudden changes of light causes.

Even if your tanks are indoors. A shed for example, if you can see in the shed without the use of lights, there is enough light to permit algae growth. It is really sneaky and a very efficient organism. Take a look around the surface of your media or the edges of your raft, if you see green or even brown (toxic) slimy stuff there it means that algae is in every part of your system, you just can not see it but it is there awaiting to take up any nutrient that crosses it path. When you are working hard to keep those nitrates up any slight increase, the algae will swipe a large chunk of that. But... the good news is, if you are using your grow bed as a primary bio filter you will at the least be inhibiting it with ammonia or more so your TAN (total ammonia nitrogen).

Personally, I do not recommend covering tanks with anything more than netting to prevent the fish from jumping out, aside from the roof that is over them.


Sidebar: Ammonia you say!? Well yes and no. Ammonia at greater than 20% of the total nitrogen is toxic to many plants (which can be a plant growth problem for those using grow beds as primary bio filters) but even more so at lower levels it will kill algae. Wait! Before we get too exited and think we can use ammonium nitrate or some such source to rid ourselves of our little green monster, other species of algae like the brown variety thrive in an ammonia rich environment and is an indicator of an ammonia problem in your system. Have I mentioned ammonia kills your fish too? Good.The tricky part is the algae does not need the kinds of levels of nitrogen that plants do. So it can stay through out your aquaponic system as long as you keep pumping the water around, back to the light. This will very effectively inhibit your plant growth. You may be thinking that your plants grow really fast in an aquaponic system, you should see them grow without algae.

Here is a little story:

I was contacted to take a look at an aquaponic system with a 2K fish tank (for want of a better term) and 10 grow beds. This was a kit system installed to the suppliers instructions. The proud owner had spent a great deal of money on a hot house an all manner of gear. It was a very moody system to say the least. A very poor design. I say this gently though with some authority as I design and install commercial aquaculture facilities (see below). That aside, adding grow beds to an aquaculture system sounded like fun and it is! However, this was far from aquaculture. It was putting fish in a tank that held water along with a lot of crossing fingers.

Unfortunately the crossing fingers did not do much to save the fish, they continued to die. I suppose this is why I was contacted. I suggested a complete redesign and retro fit in an attempt to get this set up running well. As the owner had already spent a considerable amount of money, I could not talk him out of dumping the tank in place of tanks designed for fish, so the result is he has to vacuum the tank every day or two. I had suggested the water pump and the air pump were too small and the system will require UV to prevent algae growth. It was declined as he was assured from another source that they were adequate.

So I changed out the system layout, plumping and a range of other gear that would suit the size of the set up. It took the owner four terrifying weeks of, calling me, messing with the system, more fish deaths and an algae bloom, pH swings and a host of other fun stuff to realize there may have been something in what I originally suggested. Hindsight, isn't it great!

Back I go... Lucky that I had planed in the plumbing that he would change his mind. The change out of the pump, air pump and the addition of UV (after nuking the algae) was quick and easy. We got rid of the algae, increased the air and water, and the system finally started to calm down as did the owner. He got more stock in (the original 20 had all gone) and is growing 300 silvers in the 2K tank with out any deaths or issues for the last 6 months. Now he can grow 70 to 80kg of fish in that tank providing he vacuums it every day where as before he would have been lucky to grow 10kg.

There was yet another problem still attached to the system (which were promptly removed later) that we had to move with a fork lift during the refit... two gravel beds 600kg each! But that is a story for another day... I tend to ramble... The addition of UV simply assists in keeping the system stable, it is not the complete answer.

To sum up: Algae is, a problem to those that want to get the most out of their system and I expect that is everyone. It will cause severe pH fluctuations, up during the day and down during the night. It can cause oxygen super saturation at high densities during the day and will consume oxygen at night leaving very little for the fish by 4am. As algae dies, which it does in mass it will add to the solids in suspension and add further bio load to your oxygen demands. It will take up valuable room in your bio filter, what every it might be, therefore reducing its capacity and effectiveness. It will absorb nutrient quicker than your plants, inhibiting growth. For its low cost and zero chemicals, in my opinion, UV is the best option for controlling algae.

The images below: These are some examples of what we do, which is of little relevance. Though the third image from the left may be of particular interest to you guys. That is the seaweed grow out part (not yet covered) of a mulloway turned black cobia/seaweed pilot program we designed. In effect, it is an aquaponic system, growing plants from the waste of fish. It was a salt water system which makes it more interesting. It consisted of 6 x 5k aquaculture tanks, protein skimmer (salt water), bio filtration, solids and micro filtration and a bunch of those black troughs. Interesting stuff!

[GaryD]

Hi Crusty,


Covering a fish tank will have no effect at all in the prevention of algae if your grow beds are in any form of sunlight, which they will be unless you are growing mushrooms.
I can't see how having grow beds in sunlight (which I agree they need to be) would impact the growth of algae.......if the media is not getting wet.


Covering a fish tank can have a detrimental effect on temperature in summer and it will negatively effect gas exchange with in the tank and the fish will suffer without a doubt.
I can see that this might be an issue if the cover is airtight but otherwise it is not a problem.


Further issues with covering tanks that contain your fish, are the constant light changes when you open it to feed or observe or for any other reason. These light changes will spook your fish, which in turn will have them displaying odd behavior that will sometimes be mistaken for agressive feeding when in fact they are swimming irregularly and are frightened. Let's not forget the stress sudden changes of light causes.
I can see that this might be an issue if the cover prevented any light from reaching the fish tank. In reality, most access barriers permit the entry of what I would describe as dappled shade......not unlike what fish would encounter in their native habitat. Fish that are swimming around in a tank with no cover are just as likely to be startled (and stressed) by any overhead movement......so I see no difference. One thing is certain......any tendency toward an algae bloom is going to be exacerbated by bright sunlight.


Even if your tanks are indoors. A shed for example, if you can see in the shed without the use of lights, there is enough light to permit algae growth. It is really sneaky and a very efficient organism. Take a look around the surface of your media or the edges of your raft, if you see green or even brown (toxic) slimy stuff there it means that algae is in every part of your system, you just can not see it but it is there awaiting to take up any nutrient that crosses it path.
While I don't doubt that algae spores are ever present, algal blooms are much less of a problem in an aquaponics system than you appear to believe.


Personally, I do not recommend covering tanks with anything more than netting to prevent the fish from jumping out, aside from the roof that is over them.
I agree that one of the purposes of an access barrier is to prevent fish from jumping out......and I'd add the following ones, too:


Less light still means less algae blooms......born of my experience.
Less air movement across the tank (without inhibiting gas exchange) means less heat loss during the night. Tanks still heat up during the day. Access barriers (and the shade they provide) may also prevent small tanks (of 500 to 1000 litres capacity) from overheating.
Access barriers prevent children and pets from getting into the fish tank......and harm's way.
They also prevent predators (cormorants, kingfishers, water monitors) from getting to the fish.



Sidebar: Ammonia you say!? Well yes and no. Ammonia at greater than 20% of the total nitrogen is toxic to many plants (which can be a plant growth problem for those using grow beds as primary bio filters) but even more so at lower levels it will kill algae. Wait! Before we get too exited and think we can use ammonium nitrate or some such source to rid ourselves of our little green monster, other species of algae like the brown variety thrive in an ammonia rich environment and is an indicator of an ammonia problem in your system. Have I mentioned ammonia kills your fish too? Good.
The tricky part is the algae does not need the kinds of levels of nitrogen that plants do. So it can stay through out your aquaponic system as long as you keep pumping the water around, back to the light. This will very effectively inhibit your plant growth. You may be thinking that your plants grow really fast in an aquaponic system, you should see them grow without algae.
I agree that algae should be suppressed for all the reasons that you provide. I repeat that, while algal blooms will happen they seem to be less prevalent as systems approach maturity.

Most systems will go through a pea soup phase at some point during their early development. Several of mine have and all that has been necessary is to stop feeding and reduce the amount of light. I've also connected a canister filter with a view to clearing up the water.

I acknowledge that a UV filter would be helpful in remedying an algae outbreak. My canister filter is fitted with a tiny one but I've rarely used it.

I've found that, having nursed systems through an algal bloom, they rarely experience them again.

I wonder if it has something to do with the various organisms in the little eco-system getting into a state of balance.


Here is a little story:

I was contacted to take a look at an aquaponic system with a 2K fish tank (for want of a better term) and 10 grow beds. This was a kit system installed to the suppliers instructions. The proud owner had spent a great deal of money on a hot house an all manner of gear. It was a very moody system to say the least. A very poor design. I say this gently though with some authority as I design and install commercial aquaculture facilities (see below). That aside, adding grow beds to an aquaculture system sounded like fun and it is! However, this was far from aquaculture. It was putting fish in a tank that held water along with a lot of crossing fingers.

Unfortunately the crossing fingers did not do much to save the fish, they continued to die. I suppose this is why I was contacted. I suggested a complete redesign and retro fit in an attempt to get this set up running well. As the owner had already spent a considerable amount of money, I could not talk him out of dumping the tank in place of tanks designed for fish, so the result is he has to vacuum the tank every day or two. I had suggested the water pump and the air pump were too small and the system will require UV to prevent algae growth. It was declined as he was assured from another source that they were adequate.

So I changed out the system layout, plumping and a range of other gear that would suit the size of the set up. It took the owner four terrifying weeks of, calling me, messing with the system, more fish deaths and an algae bloom, pH swings and a host of other fun stuff to realize there may have been something in what I originally suggested. Hindsight, isn't it great!

Back I go... Lucky that I had planed in the plumbing that he would change his mind. The change out of the pump, air pump and the addition of UV (after nuking the algae) was quick and easy. We got rid of the algae, increased the air and water, and the system finally started to calm down as did the owner. He got more stock in (the original 20 had all gone) and is growing 300 silvers in the 2K tank with out any deaths or issues for the last 6 months. Now he can grow 70 to 80kg of fish in that tank providing he vacuums it every day where as before he would have been lucky to grow 10kg.

So, are you suggesting that the system was failing just because of the presence of algae (or was that simply a symptom of other issues)? Are you suggesting that the addition of a UV filter made the difference that moved the stocking rate up to 70 - 80kg.......or were there other factors? If there were other factors, can you elaborate?

It seems to me that if you modified the system to the point where it will sustain 70 - 80kg of silver perch, it has (in backyard food production terms) to be judged a success.......regardless of the fish tank. What stocking rate would you expect to have achieved in a proper aquaculture tank.....and what other equipment would have been necessary to achieve it?


There was yet another problem still attached to the system (which were promptly removed later) that we had to move with a fork lift during the refit... two gravel beds 600kg each! But that is a story for another day... I tend to ramble... The addition of UV simply assists in keeping the system stable, it is not the complete answer.
What was the issue with the grow beds? I would have thought that the nitrate production possible in a system of that size (particularly with a fish biomass of 70 - 80kg) would have easily supported 10 such grow beds.


Gary

[Crusty]

As I said it is a matter of choice, Gary. Use UV or not. I have not suggested it is a must in your designs, I suggested that in my experience I have found it to be beneficial to the performance and for good reason. Where as your experience has identified that algae is not an issue.

It appears to me that we are seeking different goals. If I may hazard a guess Gary, you are looking for a harmonious balance between plant and animal in a symbiotic eco-system. At least that is the gist of your blog. A worthy challenge indeed. Me, on the other hand, I am interested in gaining the maximum production which requires some control over the entire culture area based in science. Neither approach is better or worse they simply have different outcomes.


I can see that this might be an issue if the cover is airtight but otherwise it is not a problem.
Perhaps I should have quantified that a little. It is not a problem at low densities though summers may pose an issue if not adequately ventilated. Though your fish tanks should not be in direct sunlight. Remember that 5deg C increase in the tank water can reduce the saturation level of oxygen by up to 1mg/L. At high densities it is a problem. It is even a problem with open tanks in the building the tanks are in. Unless CO2 is striped out, it builds up, reduces the pH and reduces the fish capacity to uptake oxygen and thereby reduce growth rates.


While I don't doubt that algae spores are ever present, algal blooms are much less of a problem in an aquaponics system than you appear to believe.
It could also be that I am looking at algae as a potential threat and prefer not to have any of it in a system not designed to carry its load, blooms, deaths or residence. My only interest is in fish, plants and the connecting bacteria. If I am wasting oxygen on non necessary organisms and processes I am wasting energy which means I am wasting potential growth. If there is a solid argument that suggests otherwise, I will consider it.



So, are you suggesting that the system was failing just because of the presence of algae (or was that simply a symptom of other issues)?
As you have said, it is the combination of nutrient and sunlight, to which it is regarded a symptom that we encourage (high nutrient with lots of sun = growing plants). Was the overall performance of the system being hampered by the presents of algae? Yes. Does the application of UV correct this? Yes. The system was also failing because it was a poor design. I doubt much thought went into it aside from here is a tank, pump and grow beds, go forth and conquer! Which I think is disgraceful. The addition of UV, as I said earlier, is not the complete answer but it does assist in stabilizing the system by preventing an unwanted organism that has a detrimental effect on small, reactive systems.


Are you suggesting that the addition of a UV filter made the difference that moved the stocking rate up to 70 - 80kg.......or were there other factors? If there were other factors, can you elaborate?
Yes. The addition of UV assists with achieving higher density. Oxygen demands used in the design of systems do not permit the addition of "other" biotics. (I feel like I am repeating myself) When running at peak density (with or without oxygen injection) there is simply no room for unwanted organisms, bacteria or otherwise. If they enter and take a hold, something else needs to leave (plants, fish or autotrophs). This is part of keeping an efficient system in balance, not hoping it will achieve it by itself. This is of very little concern if you are running really low densities.

There was a range of filtration installed based on standard aquaculture practices that also contributed. These would not differ greatly from your QLDer design aside from efficiency and component placement.

Sidebar: If I may make a suggestion: Though not my filter of choice, I would suggest if you must use work horse trickling filters, you combine a moving bed filter in a proportion of the total surface area required (1/3 trickling 2/3 moving bed). You may find the combination of two types a beneficial redundancy inclusion in your eco-system.


It seems to me that if you modified the system to the point where it will sustain 70 - 80kg of silver perch, it has (in backyard food production terms) to be judged a success.......regardless of the fish tank. What stocking rate would you expect to have achieved in a proper aquaculture tank.....and what other equipment would have been necessary to achieve it?

It is a success if it can reach those targets with less than 5% mortality within the standard grow out period. Until then, I will support the owner with our collective know how to achieve that outcome.

Proper aquaculture tank? Not sure there is any other type, though there are those that profess watering troughs are aquaculture tanks in their marketing of systems. Just the same, I would expect to achieve similar densities with an aquaculture tank though it is achieved with a great deal less risk, much less maintenance and of course less retrofitting. In this case, the owner will have to vacuum the tank out every day or the system will not reach its potential capacity.

You can use any tank you like but there are some basic rules in their shape and the speed at which the water moves through them, exchange rates and the relevant retention times. Species of fish is also a consideration. Some shapes will perform better than others, with round tanks the most efficient (though not so good on space efficiency). If you don't apply these basic principles your systems capacity will be greatly reduced.

Aquaculture tanks are specifically designed to remove solids at the fastest rate possible, regulate even oxygen distribution and velocities. This is achievable, though somewhat more difficult with just about any form of tank but not all.

For example there is an aquaculture farm which invested in 100,000 liter tanks (11meters diameter x 1.1meters depth). They neglected the tank size ratio principle and have now discovered they can not remove the solids from the tanks. Now they have a range of animal health issues that require veterinarian services and more costs to change inlet manifolds etc.. All in the name of saving a few bucks.

Aquaculture tanks already have the design features done for you, so they are relatively plug and play. Where as the round stock water troughs with a submersible pump in the center, or the square nally bins with an outlet at the side, or a rectangular fiberglass tank with an outlet at the top in one corner , are all examples of what not to do. Will they hold fish? Absolutely. Bang for buck on production capacity, the aquaculture tanks win hands down. I still have to use power to run the pumps so I may as well grow 2 to 3 times the fish for similar power requirements in the same space.

I am interested to see what density you expect to achieve in your new design Gary.


What was the issue with the grow beds? I would have thought that the nitrate production possible in a system of that size (particularly with a fish biomass of 70 - 80kg) would have easily supported 10 such grow beds.

Keep in mind that the design of the system is to process the waste of the end harvest standing stock weight of 70 - 80kg. There is not yet that bio mass in the system. Though the nitrate production is a little low, all the plants are growing well with assistance from foliage spray. The issue with the gravel beds is they were gravel beds that originally had solids being dumped into them. Even after the retro fit, the system would not stabilize. After they were removed it ran as expected. When the two gravel beds were emptied, there was a wheel barrow full of toxic effluent sludge after running for 2 months with barely any load, though I suspect the gravel did not wash well before use.

Some may say that removing solids is a waste of equipment time and money. Even the "Gurus" are saying it! What is the average Joe to believe?. I know I do not agree unless you are doing some serious water changes or are keeping very little stock. The level of stock (feed) is related to the length of time it takes for the solids to cause you an issue. If you are pumping your solids, that time will shorten drastically. Worms or no worms approx. 50% of your Biochemical Oxygen Demand is in those solids the other 50% is digested in your bio filtration. To use this as a very simplified example only applying the BOD, you could say that if you can safely grow 30kg of fish per 1000liters of water with adequate filtration, one can also say without that solids filtration you will struggle to achieve 15kg. Not to mention the potential "organic bomb" waiting release upon your fish.

That is only a very small part of the calculations required to design and efficient system. So remove the solids and process them outside of the closed loop. Reintroduce the inorganics after they are processed in an aerobic or anaerobic digester, the heterotrophs don't care which. That makes more sense than ignoring them and hoping they will go away.

Nasty nasty stuff.
Cheers
Paul V

[GaryD]

Hi Paul,

Thank you for your detailed response.


It appears to me that we are seeking different goals. If I may hazard a guess Gary, you are looking for a harmonious balance between plant and animal in a symbiotic eco-system. At least that is the gist of your blog. A worthy challenge indeed. Me, on the other hand, I am interested in gaining the maximum production which requires some control over the entire culture area based in science. Neither approach is better or worse they simply have different outcomes.
You're right.....I am seeking balance but, as my posts make clear, I'm also interested in reasonable productivity.

I'm not resisting the idea of UV clarification for its own sake. If I can see a clear benefit in it I'll adopt any technology in a heartbeat.

While I take your point about things being based in science, I would suggest that conventional aquaculture has its own snake oil salesmen and equipment that is grounded more in myth than reality.

I know of a commercial aquaponics facility that is full of foam fractionators, UV clarifiers, ozone devices and all of the other trappings to be found in a aquaculture supplier's catalogue. They all lie idle in half of his tank shed and the farmer has moved to a UVI-style of operation to make his system pay.

The challenge with aquaponics is to be able to reconcile fish and plant growth at useful production levels while avoiding the capital expense, disease, chemicals, power bills and sleepless nights that are a feature of many aquaculture systems.

The issue for many of us will be sorting the fact from the fiction regardless of whether we are speaking about aquaculture.....or aquaponics.


If I am wasting oxygen on non necessary organisms and processes I am wasting energy which means I am wasting potential growth.
OK.....this makes sense but let's remember that, for the most part, we are talking about backyard food production systems. I guess it comes down to how much one should spend to deal with potential issues and whether, by taking an eco-system approach, we can't achieve affordable and sustainable alternatives.


(I feel like I am repeating myself)
I can relate to that. Since you run your own forum, you should be reconciled to the fact that not every explanation is fully understood first time round.;)


There was a range of filtration installed based on standard aquaculture practices that also contributed. These would not differ greatly from your QLDer design aside from efficiency and component placement.
You have to know that making a statement like that is going to elicit a request for more detail.


Though not my filter of choice, I would suggest if you must use work horse trickling filters, you combine a moving bed filter in a proportion of the total surface area required (1/3 trickling 2/3 moving bed). You may find the combination of two types a beneficial redundancy inclusion in your eco-system.
I use trickling filters because they are cheap, easy to build and maintain......and they work. In my first Queenslander designs, the bio-filters are supported by grow beds which also support nitrification.

If you read my Baby Q (http://www.aquaponicshq.com/forums/showthread.php?2020-The-Baby-Q) thread you'll see that I've chosen Moving Bed filtration for that system. I'm still fiddling with it to get optimum performance. One of the difficulties that I'm experiencing is a shortage of available information on the practical application of the process.

At the end of the day, what I'd like to achieve is the mechanical and biological filtration performance of a product like the Nexus 3000 without the exorbitant price tag.


Aquaculture tanks are specifically designed to remove solids at the fastest rate possible, regulate even oxygen distribution and velocities. This is achievable, though somewhat more difficult with just about any form of tank but not all.

Aquaculture tanks already have the design features done for you, so they are relatively plug and play. Where as the round stock water troughs with a submersible pump in the center, or the square nally bins with an outlet at the side, or a rectangular fiberglass tank with an outlet at the top in one corner , are all examples of what not to do. Will they hold fish? Absolutely. Bang for buck on production capacity, the aquaculture tanks win hands down. I still have to use power to run the pumps so I may as well grow 2 to 3 times the fish for similar power requirements in the same space.

In backyard food production systems the solids removal, oxygen distribution water velocity and other (entirely appropriate) objectives have to be reconciled with other things like efficient use of space, cost and even aesthetics.

Interestingly, while you suggest that stock water troughs, Mega bins and rectangular fish tanks are all examples of what not to do, I have been able to grow useful quantities of fish and vegetables in all of them. Could it have been done better? Not a doubt.

I recall in a previous conversation some time back you offered to provide a retro fit design for a Mega bin system that would improve its performance. I've eaten a lot of fish and salad meals out of those sorts of systems since that conversation.........and I'm still waiting for the suggestions.;)


I am interested to see what density you expect to achieve in your new design Gary.
Since everything that I do is experimental, I won't know what it can do until I get there.....and my systems are constantly changing and evolving. In the meantime, as I said, I keep eating clean fresh food as I journey toward the ultimate aquaponics system.


Some may say that removing solids is a waste of equipment time and money. Even the "Gurus" are saying it! What is the average Joe to believe?. I know I do not agree unless you are doing some serious water changes or are keeping very little stock. The level of stock (feed) is related to the length of time it takes for the solids to cause you an issue. If you are pumping your solids, that time will shorten drastically. Worms or no worms approx. 50% of your Biochemical Oxygen Demand is in those solids the other 50% is digested in your bio filtration. To use this as a very simplified example only applying the BOD, you could say that if you can safely grow 30kg of fish per 1000liters of water with adequate filtration, one can also say without that solids filtration you will struggle to achieve 15kg. Not to mention the potential "organic bomb" waiting release upon your fish.

That is only a very small part of the calculations required to design and efficient system. So remove the solids and process them outside of the closed loop. Reintroduce the inorganics after they are processed in an aerobic or anaerobic digester, the heterotrophs don't care which. That makes more sense than ignoring them and hoping they will go away.
You'll be pleased to note that I am not one of the people saying this (and nor do I attach to the term "guru"). We are in complete agreement about the need to remove solids for external processing.

The challenge is to achieve this cost effectively.

Gary

[Crusty]

Hi Gary.

Just want to touch on a few things in this reply as the rest has become somewhat circular.



While I take your point about things being based in science, I would suggest that conventional aquaculture has its own snake oil salesmen and equipment that is grounded more in myth than reality.

I know of a commercial aquaponics facility that is full of foam fractionators, UV clarifiers, ozone devices and all of the other trappings to be found in a aquaculture supplier's catalogue. They all lie idle in half of his tank shed and the farmer has moved to a UVI-style of operation to make his system pay.

I know of the farm you speak about and just the mention of a foam fractionator in a fresh water system speaks volumes. Indeed there are plenty of companies out there praying on the ignorance of the masses, even in such a small industry as aquaponics, there are a greater number to volume of sale. On the other side of the coin, we have people come to use and say, "I want this, this and that", when the answer to why, suggests the equipment requested does not match the purpose of use, we will promptly tell them. Many of them do not want to listen and buy what they "want" not what they "need". So it is easy to lay blame on the equipment supplier for their failures.

It may be thought that I have an other motives in as much that we design and sell aquaculture equipment, however we have never built anything that has failed. If a farmer asked me what potential load can be expected from a system design, I can hand them the magical number and offer the math that supports it. A potential farmer should already have a grounding in the science. If they want to do something that will not work, we do not get involved. For example, I am charged with calculating filtration requirements of possibly the first fully recirc crocodile farm in Australia. From initial input and output calculations, the type of filtration required may be outside our scope and we may pass it on to those who have more suitable waste water applications. Before that decision is made, the potential farmers have to provide me with more info on the waste production of salt water crododilians, as I admit I know nothing about them but the design process is exactly the same regardless of species.


The challenge with aquaponics is to be able to reconcile fish and plant growth at useful production levels while avoiding the capital expense, disease, chemicals, power bills and sleepless nights that are a feature of many aquaculture systems.

The issue for many of us will be sorting the fact from the fiction regardless of whether we are speaking about aquaculture.....or aquaponics.
To carry on from the previous paragraph, aquaponics is not dealing with anything new, such as an unknown crocodile species which the RIRDC only have basic basic output knowledge. The information for both aquaculture and hydroponics has been well established for a wide variety of species, and more so recently it has been research academically. There are plenty of misconceptions plastered everywhere on the internet. A great many of these are apparent in aquaponics.

As far as capital expense goes with aquaculture, if there was a less expensive means of retrofitting some other cheaper tanks (IBC for example), they would be using them. They don't because the design principles are fact and you can quickly go from 200kg/m3 plan to a very broke 100kg/m3 reality.

I suggest perhaps involvement with your local wildlife and fisheries (DPI), they will provide you with adequate information packs on a variety of different species. I am certain that the hydroponic industry has a regulating body that may also be of assistance when studying the nutrient uptake of different plants.

This information is not some secret squirrel that can not be gathered with a few phone calls. Take the nutrient output of fish species, match it to the nutrient uptake of the plant species and add the difference.



You have to know that making a statement like that is going to elicit a request for more detail.
Indeed and I had written a more detailed response. Knowing people tend to be proud of their inventions and designs they can be easily offended, I though it best to first understand the logic you have applied to the configuration. I understand how each component works but its placement in the water flow is a mystery to me.

Fish (orgainics)-> solids (hetero)-> nitrification (auto)-> denitrification (plants)-> oxygen (sump)-> buffer (sump)-> fish (happy). There are a few sub systems as well but that should be the basics of the design.




Interestingly, while you suggest that stock water troughs, Mega bins and rectangular fish tanks are all examples of what not to do, I have been able to grow useful quantities of fish and vegetables in all of them. Could it have been done better? Not a doubt.

I recall in a previous conversation some time back you offered to provide a retro fit design for a Mega bin system that would improve its performance. I've eaten a lot of fish and salad meals out of those sorts of systems since that conversation.........and I'm still waiting for the suggestions.;)
As I recall you were not removing solids at that time and I made it very clear the system you were using needed to do this to get the best out of it and offered the approaches that could be taken to achieve it, such as swirl filters, removing the pump out the fish tank, bottom draining, settling tank etc. I did suggest that I can design a retrofit for the tanks you were using and design adequate filtration. However unfortunate, you can appreciate paid work takes precedence over freebies.

Cheers
Paul V