My New System

[POC3442]

Photo 1 shows the inside of the barrel with the inlet arrangement in place. In the interests of simplicity I'd dispense with this and use a 90 degree bend......like the one that is in my swirl tank (Photo 2). You can see the dump outlet in the bottom of the blue barrel.
Photo 3 shows the laundry basket in place. It is lined with filter foam and coral is placed in the bottom of the basket.
Photo 4 shows a build up of solids in the base of the barrel.
Photo 5 shows the inside of the laundry basket when the filter is operating.

So, do you leave it open or also have the basket....I'm not 100% sure what the basket/coral is doing(my understanding from what you types and observed is the filter mat prevents larger particles from getting into the coral. The coral then prevents solids from getting into the moving bio-filter...which should be crystal clear water by the time it gets there...however this would cause for some cleaning whenever it gets dirty. If it was just the inlets and outlet like in yours no cleaning of the internal components are required. Any reason it could not just have it all open? Or would this not allow the particles to settle out?

What is the basket resting on? The top of the pipe coming into the barrel I presume? If so won't this put a lot of pressure on your fitting to the barrel possible causing leaks after a while?



A swirl filter is designed to allow removal of the solids every few hours if necessary.....before oxygen is lost in their digestion. While mineralising the solids in the system (by using a clarifier) runs contrary to my preferences, it still traps the solids and prevents them from building up in your grow beds.

Since this is a hobby and not a job I could foresee cleaning it daily; but how often do you find yourself cleaning yours out? Granted when the 50 fish are fry it would be cleaned out less often then when they were about 2 lbs.





While a cone is the ideal shape for the bottom of a swirl tank, it's not essential. The other possibility is to make the swirl tank small enough (say 20 liters/5 gallons) that, when you want to clean it, you just stir up the entire tank an dump it. I like that idea...but i think it would not be too hard to make the bottom a cone shape...I'll at least try if I fail I'll just use a regular bottom...but either way I'll report back the news.




As to pipe sizes, for a small system like yours, you might get away with 3/4" but I'd prefer to see you use one and a half inches throughout. While 3/4" seems quite large initially, you should remember that it will become lined with bio-film after a short time and that will inhibit the flow of water

Even for on the inside of the fish tank? I figured you would want a smaller pipe size to create more suction so that you could more easily pick up solids. But seeing as i do want to one day add another tank and such it would make sense to stick with 1.5 inch pipe.

Thanks a lot,
POC3442

[GaryD]

Hi POC,


So, do you leave it open or also have the basket....I'm not 100% sure what the basket/coral is doing(my understanding from what you types and observed is the filter mat prevents larger particles from getting into the coral. The coral then prevents solids from getting into the moving bio-filter...which should be crystal clear water by the time it gets there...however this would cause for some cleaning whenever it gets dirty.

The design of the filter is such that it allows the sedimentary solids to settle out and the suspended solids to be trapped on the filter foam. My guess is that the coral holds the filter foam in place and is possibly an attempt to buffer pH.

The water passes through the filter foam into the basket. The clean water exits the filter through the pipe at the top. Since the foam is intended to trap the suspended solids it is logical that it will need cleaning periodically.


If it was just the inlets and outlet like in yours no cleaning of the internal components are required. Any reason it could not just have it all open? Or would this not allow the particles to settle out?
The photo of my swirl tank is purely to show you how the water enters the tank (rather than the more complicated arrangement in Dave's filter. I have used a packed media attachment to this filter which does the same thing that the filter foam set up in Dave's unit does.


What is the basket resting on? The top of the pipe coming into the barrel I presume?
The basket is supported inside the barrel.....the top of the basket is such that it rests on the top of the barrel.

Gary

[POC3442]

Bulkhead fitting question. So I am trying to figure out how exactly I have a 1.5 inch pipe go from the center of my fish tank through the fish tank then to the barrel through it blah blah. http://www.enkoi.com/Bulkhead-Fittings-Plumbing-And-PVC-sc-147.html is a link to the bulk head fittings. They all seem the same. The only problem I see is that there is no way to connect pipe to it on one of the sides. For example; I can use a threaded PVC pipe to connect it to the bulk head fitting inside the tank but on the outside it's just flush. Maybe I'm totally missing something but can't seem to figure this out. Since there are no stores around here that sell them I'm going to have to order them online.

[GaryD]

Hi POC,

This is the sort of tank outlet (bulkhead fitting) you're looking for........here (http://www.hansenproducts.co.nz/products/thread/SFTFT.htm). As you can see, it allows for fittings to be screwed on/in from both sides.

Your other option is the Uni-Seal......here (http://www.aussieglobe.com/uniseal1.htm). It comprises a special ring that you push PVC pipe through.....allowing you to glue your choice of fittings to the pipe. We used them extensively on our Mega Bin System.

W've covered a lot of ground since this discussion started. Do you want to provide me with a description of your final design before you start spending money......just to make sure?

Gary

[POC3442]

Any tips for the uni seal? Looks pretty simple and straight forward as well as cheaper than book head fittings. Are they reusable?

[GaryD]

Hi POC,


Any tips for the uni seal?
Yeah......get someone else to install them. Paul (Crusty) did mine and they take a bit of effort to insert. At the end of a long day, his hands were not in good shape.


Looks pretty simple and straight forward as well as cheaper than book head fittings.
They are cheaper than bulkhead fittings and, depending on the situation they are tidier, too. If you're putting a more sophisticated system together (like the Mega Bin System), and you're using a lot of them, they are faster to install than the equivalent number of bulkhead fittings. If you look through that system thread, you will see where we used lots of them. Picture what would look like if you had to use bulkhead fittings.



Are they reusable?

To a limited extent. They develop a 'memory' from their original use but, based on my observations of Paul, they can be massaged about a bit. He warmed a couple up and gave them a tap in a couple of places to get them to settle in a new application.

Gary

[POC3442]

Questions I still have:
How often do you feed Tilapia? I've read that the large scale places on fry do it upwards of 5-6 times per day. Once per day is still fine no? Just not as good of growth?

To help keep nitrates down is it ok to put water hyacinth in the swirl tank above the basket? Should also help filter out any particles and since they are prolific growers should help out some?

How do you know how much to feed the fish? I was reading This Article (http://aquanic.org/publicat/usda_rac/efs/ncrac/ncrac114.pdf) which stated that
Size of fish (grams) Amount of daily feed (% of fish weight)
0–1 30–10%
1–5 10–6%
5–20 6–4%
20–100 4–3%
larger than 100 3–1.5%
How do I even estimate how much the fish weigh in grams without taking them out of the tank. Which I won't do because I don't want to stress the fish.

Also according to the above article If I grow my fish out to 2-2.5lbs=907-1133grams each. This would mean that with 50 fish would weigh between 45.35kg and 56.65kg. Which at 1.5% per weight to feed them would be between 680 and 849 grams and double that if I was feeding at 3%. Now you know how I plan on having my system with the grow bed size being small and I will have a swirl tank as well as a moving bio-mass tank as well. My question is if I only use 50L of K1 Kaldness which according to the website "50 litres can process 250 grams of high protein food per day".
Also found on the K1 site this quote "It is possible to use no less than 30% to a maximum of 67% of this volume with K1. An average of 50% is recommended." This would mean the minimum K1 I should have in my 204L barrel is 61L and maximum is 136L of K1.

If I am feeding the fish 680-849 grams and it can only process 250 grams will I be in trouble? Should I seriously consider buying 75 or 100 liters?

I also found this

Lastly swirl tank. How often do you empty this? I am sure the more often the better but how often do you do it?

Crushed Coral as a pH buffer. According to Aquahobby (http://www.aquahobby.com/articles/e_adjusting_pH.php) to buffer your water using crushed Coral you need to put 1kg per 40 liters. That would be 20 kg of crushed coral! According to websites would take up about 13x13x12.5 inches. Basicly a cubic foot. The pH would be around 7.6 which seems on the high side. Any thoughts?

[POC3442]

Well I figure it's about time for me to give you guys an update. My fish supplier here in Illinois is shutting down for the winter...so instead of getting them for .33 for a 3 inch Tilapia I'll have to pay more. Oh well that life. I rebuild my system hopefully making Gary proud. I think it'll not only help me have a few more fish than my setup before but also keep the water cleaner. I'll post my video as soon as I get it uploaded.

[POC3442]

Well after a 2 day battle with my internets...I have finally prevailed!


http://www.youtube.com/watch?v=fNPnVbRGWfU

[GaryD]

Hi POC3442,

Your system is looking great......and your video makes it very easy to see what's happening.

Give yourself time to get that bio-filter working properly.

The K1 media will take some time to condition. Not only does it float but it needs to get a bit "dirty".....so throw a good handful of feed into your swirl filter and let it decompose.

Once the K1 media has been in the water for a while, it will sit down in the water a bit better.....and your air will get it to start to work properly. Picture the way that something moves around a cooking pot when it is just simmering (not boiling hard) and that's what you want to achieve with your K1.

How much of it do you have in that drum?

Gary

[POC3442]

I would of never thought of throwing some food in the swirl tank...figured that would be a bad thing but I guess when it breaks down it'll create more ammonia so it'll just supplement me adding ammonia to the system until it cycles and I get my fish. As far as cycling goes...if it cycles next week and I won't get my fish in it for another month (looking at getting fry and raising them in a smaller tank then putting them in the larger one) is OK to stop adding ammonia to the big tank or do I need to keep adding it to keep the bacteria all happy and alive?

I have 50 Liters of K1 in the 55 gallon drum. For a 55 gallons of water you should have 70 liters of K1 but they only sell it in 50 and 100L. Also the water is never at the top in the moving bio filter drum anyways so it's more like 40-45 gallons.

[GaryD]

I would of never thought of throwing some food in the swirl tank...figured that would be a bad thing but I guess when it breaks down it'll create more ammonia so it'll just supplement me adding ammonia to the system until it cycles and I get my fish. As far as cycling goes...if it cycles next week and I won't get my fish in it for another month (looking at getting fry and raising them in a smaller tank then putting them in the larger one) is OK to stop adding ammonia to the big tank or do I need to keep adding it to keep the bacteria all happy and alive?
I'd usually prefer to use pure ammonia to cycle a system but it's not as readily available as feed.....and it has another benefit in your situation.

Your moving bed bio-filter needs to get a little dirty to work properly....bio-film builds up on the surfaces of the tiny media and this is where the nitrifying bacteria live.

In any case, feed is what drives your system once you put fish in it......so you might as well cycle the system using the same stuff.

The logic of using feed this way eluded me, too.......and then Crusty (with whom I was discussing moving bed bio-filters) connected me with the need to get the media 'dirty' to get it working.

If you put the feed into your swirl tank, you'll contain the sludge while all of other other things you want from it will spread through your system.

Gary

[POC3442]

Ok so I've been trying to cycle my system. Added feed and I'm stuck. I added maybe too much Urea. Still no fish in it yet.
pH 8 . Currently using 1M Hydrochloric Acid to try and get it down.
Ammonia 0
Nitrite 5+
Nitrate 80 ppm

I added the Urea a week ago going to keep watching my Nitrite but doesn't seem to even go very low. Any suggestions?

[GaryD]

Hi POC,

Your nitrite levels suggest that you might have been too generous with the urea......particularly in light of the 0 reading for ammonia.

Don't worry about the pH at this stage.....you don't have any fish in the system so you won't do any harm.

Don't add any more urea. At some point, the ammonia and the nitrite levels should both drop to zero. The presence of nitrates suggests that your system has cycled.....so let's wait till the nitrite levels settle a little before we do anything else.

Let things settle rather than changing things too quickly. Keep reporting your readings over the next few days.

Gary

[POC3442]

Sorry I have not posted...my internet has been down as of late. But that being said seems like everything stabilized out. I'm still stuck with a high pH though. And my zucchini plants seem to be taking up the nutrients just fine in the higher pH water. If they continue to do OK I might just not mess around and leave the pH around 8. As I'm sure it'll naturally go down when the fish have been in there for a while.

[GaryD]

Hi,

Things will start to drop once your fish get some size on them and you start to pour the feed into them.

Gary