Backyard Aquaponics
A place to discuss aquaponics

Thought of a way to test it out once the bacteria gets established. Drop it into a drum with a high ammonia level and then time how long it takes to convert the water. It then occurred to me that as this is on the end of a 10mtr air tube it can be moved into any FT that has a problem with filtering. And once the levels have lowered it can be dropped back into the pool. Might be a good thing to have when restocking different tanks or when shit happens eg spikes or bacteria die off.

Going to be building a bigger version. Using a section of a blue drum (40cm ish) and tieing too bread crates to each end to keep the bio balls inside it. Not sure if I should use air stones this time or just drippers attached to a coil of 13mm poly in the bottom. Will have to try it in the pool to see if it floats or if it needs a little help. Will hold 1.5 to 2 thousand bio balls ish. And a lot of water will hopefuly move through it per hr.

The smaller test one is still running after 3 months without blocking. No idea how well it converts ammonia or nitrite. If I have time I will throw it in a bucket and see how long it takes to process ammonia.

Dufflight, awesome idea you came up with here. I have another use for it. My tank! I have much more water than I am pumping through the growbeds but to the other extreme. I have a 10 gallon tank that will be using my minigeyser pump found elsewhere on the forum. It will be pumping about 2 gallons per hour with the air pump I have through the shoebox size growbeds which are also filled with small river gravel so they will do some filtration, but i heyjust won't see much water fast. I have another smaller air pump that I could use for this "airlift biofilter".

I figured out that if I can't move the water past the biofilter fast enough, maybe I could move the biofilter past the water. I tried making a reverse water wheel that worked off the air turning it in the water and was going to attach filter material (quilters poly batting has the most surface area of any filter) and rotate that in and out of the water on the wheel. Only thing is the wheel worked but when I attached the filter material to it, it weighed too much for it to operate. The wheel just didn't turn with the extra weight of the water that the filter was retaining at the top of the wheel. If anybody has any ideas on moving filter material, bring on the new concepts, please let's hear them!

Well since the demise of this attempt, I hadn't thought of another way to move the biofilter but your idea seems like a great one to get extra bio filtration! And it helps move the water as a bonus! The minigeyser pump just doesn't suck enough through it to really have a filter around it be beneficial. The airlift biofilter sounds just like what my system needs.

Try putting the wheel in the water sideways so the wheel doesn't have to lift the filter material out of the water just move it around on the surface.

Biggest issue I see with this type of filter is that algae may tend to grow on it.

ya know, for extra filter capacity you can always prop a bin, bucket, barrel or whatever at the edge of the fish tank/pool and the bypass water can be run through that container filled with whatever material you have on hand. I know of some commercial size operations using trash cans or barrels of shade cloth as bio filters. Heck if it is really just bio-filter surface you need and not solids filtering, you can even just throw the filter material into the tank and let it float around though it might tend to grow algae that way.

The wheel won't work sideways, it worked using air pushing inverted plastic shot cups up while the empty cups filled with water coming down the other side. I figured the device would help aerate the filter and move some tank water, but it didn't work when put to the test.

Floating filter doesn't move much without other water movement. I tried that. Plus the two minnows I had seemed to get stuck in it. Course I did have large parts at the time.

Algae, that's another issue I have. My system readings are good but algae doesn't grow. I even added some string algae from the local river on purpose. It eventually found its way to the filter. It stayed green but never multiplied. My tank is a glass aquarium fish tank sitting right in front of a window with miniblinds that are closed. I plan to cover the tank sides but haven't needed to at this point. It is a little boggling. No algae normally indicates something wrong somewhere. Any ideas on that one?

If you have functioning grow beds and there was a little algae that died and has been digested in the grow beds, then the byproduct of that old decomposed algae may have the effect of inhibiting algae growth to some extent. Then again, algae also needs nutrients, how are your nitrate levels?

The idea to totally sound. I use an aquacube and it is essentially the same thing, only it uses baffles rather than bioballs. When you do the calculations for a 10000 gallon tilapia tank, you need to move about 50 GPM through the bio filter to convert enough ammonia for 5000 adult tilapia. That is a lot of pumping power and bed space. An aquacube can move well over 50 GPM through itself with just air lift and sits nicely in the center of the tank. Now a more reasonably sized pump can be used to move water to the growbeds for nitrate/phosphate removal without fear of the ammonia and nitrates. Does a great job of keeping the O2 levels high as well.

Well, I'm about to add the first growbed to it this weekend. I haven't found any algae that has turned to brown. I threw some of it out but still see small pieces in the filter from time to time when I'm moving it around. Nitrates have been around 10 - 15. I have two ivy clippings in it (because I can't get seeds to germinate using baggie method, dangit!) although it is difficult to tell if they are doing okay at this point. They've been there for a week or two but don't look like thriving clippings. I assume that was caused by lack of other nutrients until I get fish in. I've been fishless cycling (aside from a minnow accident last weekend that caused at pH 2.0)

Was going to sink a 200ltr olive drum with small holes around its base and fill it with gravel. The 5000lpr pump that has a foam jet can just dump water into the top of the drum. Should have enough o2 to keep the bacteria going and the flow should be good.

Been running the new filter for a few days now and have seen a drop in the Am and Ni. Some of the bio balls were from storage so over the next couple of weeks the bacteria should cover more of the surface area and get an even better result.(if I knew it was going to work this well I might have made it pretty)
Will be harder to tell how well it is doing once the next GB's get installed.

Well I made an airlift biofilter. Used a plastic V8 bottle (about 2 liters). I put gravel in the bottom to keep it sunk, cut a square hole above the gravel level about once inch high and 3-4 inches wide for water to come in. Stuck an air stone to the bottom in from the top and pushed all of my poly batting into it. Seems like its okay, still too early to tell. I'm thinking bioballs or something floating might work better for an airlift biofilter, but then again, maybe not. Neither material will move once it is all in place just it's a matter of how much material the air bubbles can hit on the way up. I haven't figured out a way to tell how much water (if any) it moves either.

And why don't some of the smilies work? :Question: :question:

They get nervous

It takes a little time for the bacteria to cover the media in the filter. Not really the material the air bubbles can hit on the way up as the water that gets moved with the bubbles. And the added o2 to keep the bactera going.

It gives new meaning to going to the oxygen bar!

Just a followup for anybody who may come across this thread. The V8 filter did not work. The quilters poly batting actually created large air pocket(s) somehow and most of it (90% +) was completely dry when I took it out and took it apart! Who would have thought that could have happened completely submerged. The top of the container was always under the water surface level. The batting provides great surface area but should probably be pulled apart and thinned for this type of use.

Mine is still going well. But I've got a different kind of underwater bio filter running now as well. Does not block up and works a lot better. Can't move Am or Ni readings and I doubled the food and added 130 fingerlings. Cooler weather is going to slow things down now.