Froggos Aquaponics

[froggo]

Hi GaryD,

One day when I was a bit bored I decided to do a system water test. When I do the tests I take water from either the sump or fishtank. This day I decided to test the water as it was returning from a growbed before it spashed into the sump.

The results showed no noticable change/lowering of ammonia, nitrite, nitrate after going through the growbed compared to readings taken from the fishtank.

This got me thinking about using the same water through several growbeds to strip more nutrients and convert more amm/nitrite without added pump time.

As part of my system expansion I decided to add several different features;
1. The system water on each pump cycle will travel through three seperate growbeds before returning to the sump.
2. The sump capacity of 1000litres and has now been increased to 1600litres and contains 600litres of constant flooded growbed.

the constant flooded growbed works in reverse to a standard growbed. It is always full of water but when the pump kicks in the growbed empties and refills along with the sump. This growbed is going to grow my water loving plants like cress.

The purpose of the change is to convert as much amm/nitrite and remove max nitrate on each cycle delivering the cleanest possible water back to the fishtank on the next cycle.

God bless, froggo

[GaryD]

Hi Froggo,

In my view, the answer to your ammonia/nitrite readings is to install more bio-filtration. This could be more grow beds buy I'd suggest that you try a trickling bio-filter.

Nitrates will always be present in all parts of your system and the only way that you will reduce them is to have more plants in the system or to regularly take water from your system and use it to water your soil-based gardens.


As part of my system expansion I decided to add several different features;
1. The system water on each pump cycle will travel through three seperate growbeds before returning to the sump.
2. The sump capacity of 1000litres and has now been increased to 1600litres and contains 600litres of constant flooded growbed.

the constant flooded growbed works in reverse to a standard growbed. It is always full of water but when the pump kicks in the growbed empties and refills along with the sump. This growbed is going to grow my water loving plants like cress.
This sounds interesting......can you produce a diagram to show how things are put together. The constantly flooded grow bed idea is similar to something that I came up except that I use a sump tank as a water garden and I don't have media in the grow tank.


The purpose of the change is to convert as much amm/nitrite and remove max nitrate on each cycle delivering the cleanest possible water back to the fishtank on the next cycle.
You will achieve the first part of your goal by positioning a trickling bio-filter between your sump tank and fish tank. As I said earlier, more plants or periodic water change will resolve the second issue.

Gary

[Crusty]

The results showed no noticable change/lowering of ammonia, nitrite, nitrate after going through the growbed compared to readings taken from the fishtank.

Hi

What were the results of the readings?

[froggo]

Hi Crusty,

the tests were done during summer when the growbeds were full and water temps were at their max which in my system is 26 deg C.
Amm .25
Nitrite .25
Nitrate 80
PH 7.4
Salt 5ppm
Fish 200 silverperch 2 years old.
Water 7000litres
Pump Times 10cycles x 5minutes, moving 850litres per cycle, 8500litres per 24hr period.

The figures never change much in my system, except nitrate which I like to keep between 60-80.

In time I'm going to connect my AP system with my fish pond to do water changes when required. I run the fishpond at
Amm 0
Nitrite 0
Nitrate 0
PH 7.4

The fishpond is packed with waterplants, hundreds of goldfish and some silvers.

Gary I will be posting some pictures when I complete the changes. I don't have a system layout plan it would take a fair bit of time to produce one.
I'm onto the last and biggest growbed and spent the day with the lazer level getting heights set so it will work correctly. The hardest part of three growbeds in series is the correct heights so autosyphons work and gravity feed into the next bed.

God bless, froggo.

[Crusty]

Hi Crusty,
the tests were done during summer when the growbeds were full and water temps were at their max which in my system is 26 deg C.
Amm .25
Nitrite .25
Nitrate 80
PH 7.4
Salt 5ppm
Fish 200 silverperch 2 years old.
Water 7000litres
Pump Times 10cycles x 5minutes, moving 850litres per cycle, 8500litres per 24hr period.

Hi Froggo.

I don't see any major issue with those numbers. Running lightly at 8(ish)kg/m3. Not sure how big your fish are but being in Vic I suspect the growth of the silvers is very slow (250grams?). One and a bit turn over per day, in my opinion is running way too slow. Increasing that flow rate (cycle time) will see those nitrigen numbers come down. How are you reading the salinity? I would attempt to push the pH. down to at least 7. But all in all it looks good from here.

[froggo]

Hi Crusty,

the hothouse helps keep the growth period to about 9months of the year. During winter my water temp can get to 10 deg C before warming up again in August.

I have not measured or weighed any of the fish but they are around 300mm and starting to build a good width/thickness/shoulder area as perch do.

The salinity is checked with a refractometer and I aim to keep the salt level at 5ppm for good fish health.

The system turn over per day is a subject where I believe there are several ways to skin the cat. In a smaller volume system you may have to turn the water over often to maintain water quality. In my system I only turn the water over enough to convert the ammonia produced by the fish load. This is the whole concept/aim of the double, triple growbeds in series mated with constant flooded sump growbeds to convert/remove max amm/nitrite/nitrate.

The PH does not seem to change and my pond is the same. I have 50kg of shell grit in my system as a buffer. I'm using some different gravel in the new growbeds to see if that will help the PH any. I'm happy at 7.4 and don't want to change it using acids but prefer to change it using growbed media. I see lots of people forever mucking about with their PH adding chemicals and it's always a short term solution.

The changes to my system are a bit of a experiment and not what you would call standard practice but it's working so far. This summer will put it to the test as I up the fish load with cod and catfish.

God bless, froggo

[ColinW]

Hi froggo - my ATC Refractometer measures salinity in ppt (Parts Per Thousand) - you have given your salinity in PPM (Parts Per Million)? I had been running my system at 3ppt but found that the vegies were not happy at that level. I have since cut salinity back to only 1ppt. Regards - Colin

[fishfood]

I run up to 3 ppt no problem

[francois]

Hi all

in my system i have never added salt
used salt when fish was being treated
but in another dam.
Treated fish and then released back into system
have no problems +-4 years

[froggo]

Hi ColinW,

Yeh I know what you mean. I tend to just go along with the way everyone else writes up their ppm because most people describe their salt as 1kg per 1000litres = 1ppm, instead of 0.001ppm or 1ppt.

So when we say 5ppm I mean 5kg of salt per 1000litres of water/ 0.005ppm.

now I'm getting confused so I better stop as it's hurting my brain.

Hi Francois, the salt is more of a preventative, to stop itch and finrot plus a few other nasties in a closed system. I agree that it is handy to put fish into a sudden dose of salt to kill bugs. In a big dam I would not use salt either.

Hi fishfood,
I started off with 5ppm to match John's hatchery where I buy the fingerlings. I've had no probs either, strawbs don't like the salt much everything else grows fine.

God bless, froggo.

[fishfood]

1 kg salt in 1000 litre is 1 ppt

[froggo]

Hi fishfood, that's correct or it can also be called 0.001ppm or what some people post 1ppm.

quote Food&Fish on BYAP forum,
"I would go for the theory different system different circumstances i run salt all the time 2 1/2 to 3 ppm 6.5 to 7 ph all the rest 000 i have different medias in the grow beds put a couple of teaspoons cleated iron every 6 weeks and a slurp of seasol every three weeks"

are these correct or do you mean ppt?

It's a common mistake.

God bless, froggo.

[Crusty]

Hi ColinW,

Yeh I know what you mean. I tend to just go along with the way everyone else writes up their ppm because most people describe their salt as 1kg per 1000litres = 1ppm, instead of 0.001ppm or 1ppt.

So when we say 5ppm I mean 5kg of salt per 1000litres of water/ 0.005ppm.....

Hence why I asked how you were reading your salinity... it is expressed as ppt (not a fan of this as ppt can also reference parts per trillion in chemistry) a clearest way to reference is mg/L or even g/L. In your case, 5000mg/L or 5g/L, this way the volume can not be mistaken.

So this addition of salt is in addition to the salts already in the system or this 5g/L is what you actually read?

[Privatteer]

I always thought it was good to run a small amount of salt for fish health ie 0.5 to 1g/L which happens to be what my town water runs at.
However I was under the impression the jump to 3 onwards was meant to be a "shock" treatment for illness and it was the rapid change that killed the infection.

[froggo]

Hi Crusty,

when I first filled my system I used mostly rain water. The PH was 6 but I don't know what the Na level was then. The fish hatchery that I got my fish from runs 5ppt salt to prevent disease so I thought I would do the same as I heard it would not hurt plants except strawberries.

I added the first lot of salt at 5kg per 1000litres and quite a time later borrowed a refractometer to check the progress. The test still showed a total of just under 5ppt.

The salt take-up by plants, no water changes and a PH 7.4 still gave me a figure similar to what I added. The unkown as I said was the rainwater sodium level.

Hi Privatteer, I had no idea about the ideal level of salt when I first filled my system. I read a bit about it on the forum and when I was talking to the owner of the fish hatchery he told me about it. I thought this guy knows his stuff and produced a great product so I emulated it.

The salt level I use does not seem to cause any issues in my system and I have only ever lost 1 silver and it had no signs of disease. I did kill some trout but that was a hardware issue with air.

The shock value of salt to kill disease I can still do in a seperate tank not linked to my plants because the fish can handle more salt, it's just the plants may not like it much.

God bless, froggo

[froggo]

Hi everyone,

things are still going great guns with my system. I now have about 200 sexually mature silver perch that I intend to breed in the coming years.
I'm about to sell my current urban 1/2 acre mini farm and move to my rural farm where I intend to build a large AP system and endeavor to breed Silver perch, Cod and Murray Catfish. I want to set up a big AP system as part of a self-sustainable farm to feed my family, friends and anyone in our local community in need as well as producing cheap fry for my AP friends and myself.
As usual this project will take some time to begin as I have to sell my old house and system before I have the cash to start the new project.
Looking forward to sharing my new system when it starts,

God bless,froggo

[Pugo]

Well, congrats with your on going system, and I wish you the best on your new project..:)