DIY Fluidized canister filter finally sealed and churning... thoughts?

[brandontw]

What tanks, gallons, livestock etc are you trying to run with this?

It's a 55gal with 18 young Mbuna.

I am under-filtered right now with a single cascade 700 canister but getting by because of small fish and good filter media. I want to add a shoal of catfish, and a tank upgrade is in the works for the future, so playing with filtration ideas now before it becomes a situation.

This 4gal container of fluidized media gives >250 SQ ft of media surface area vs the <50 SQ ft of 30ppi foam I have in the canister now.

 

[Cal Amari]

Hmmm, well I'm no expert on filtration but for a 55 with mbuna, even at 18 and adding catfish I can't imagine needing a fluidized reactor. There's lots of threads here about people trying to figure out maximizing surface area and cramming as much biomedian as they can into a filter, but from my limited experience, and comments from other very experienced aquarists such as duanes , i believe once a tank is fully cycled it's a fairly small amount of biomedia actually needed, the bacteria only expand to the size of bioload provided, and they won't expand beyond that despite how much media is there. If you're still having ammonia or nitrite readings after maybe 6 months of operation then perhaps you need more biomedia, but less time could mean your cycle just isn't complete, or if it's nitrate you're worried about, bio won't help. Water changes and plants are the only solution. Or if water clarity is the issue then you need more mechanical filtration.

Anyhow still a cool experiment and contraption to get working, but You might need to clarify the specific filtration issue to see if you're solving anything.

 

[brandontw]

Hmmm, well I'm no expert on filtration but for a 55 with mbuna, even at 18 and adding catfish I can't imagine needing a fluidized reactor. There's lots of threads here about people trying to figure out maximizing surface area and cramming as much biomedian as they can into a filter, but from my limited experience, and comments from other very experienced aquarists such as duanes , i believe once a tank is fully cycled it's a fairly small amount of biomedia actually needed, the bacteria only expand to the size of bioload provided, and they won't expand beyond that despite how much media is there. If you're still having ammonia or nitrite readings after maybe 6 months of operation then perhaps you need more biomedia, but less time could mean your cycle just isn't complete, or if it's nitrate you're worried about, bio won't help. Water changes and plants are the only solution. Or if water clarity is the issue then you need more mechanical filtration.

Anyhow still a cool experiment and contraption to get working, but You might need to clarify the specific filtration issue to see if you're solving anything.

Yup, I get all that. I have an automatic water change system set up, so nitrate is not a big concern... I'll just adjust the amount of water changed to keep the nitrates at reasonable levels.

I also agree that the amount of biomedia required for ammonia oxidation is relatively small in most tanks. I am aiming for "overfiltration" so that additional dissolved organic compounds can be absorbed by the biomedia for clearer, healthier. My goal is to have almost no mechanical filtration, but just a ton of bio to see what can be done with just biofiltration.

 

[fishdance]

You have confused a fluidised filter with a moving bed bio reactor (MBBR) which is not surprising as many people do and both look similar at first glance.

The fluidised filter encourages young actively growing bacterium by mechanical abrasion of filter media. You will see a distinct colour change in the media zones once established. Sand is mostly used as media but HDPE granules either buoyant or sinking can be.

MBBR is a biofilm filter so you want to encourage established mature complex bacterium that has developed specialised roles. K1 media and numerous variants all which have protected areas to prevent mechanical abraision. MBBR are most effective tumbling so the media can get multiple passes per single pass of water. Another example of biofilm filtration is the dated trickle filter. Unfortunately MBBR work best alone, not in conjunction with other biological filters - anoxic, fluid, etc. And they need air. Don't close them off.

Both very effective if used correctly.