I just set it up again today on a tank with no algae scrubber so I'll be testing it as the only biological filtration with another canister filter in line before it with physical sponge filtration to keep the BCB canister filter extra clean. I've noticed a few things that seem to be consistent among BCB adventurers.
- BCB's seem to initially absorb nitrate somehow before they're fully cycled. People think it's working already and then it seems to stop but the bacteria is just still developing.
- Cycling time for ammonia and nitrate is the normal 6-8 weeks with some anoxic bacteria at that time but then the "deeper" anoxic bacteria start to build after that. I would say 3-4 months for a full anoxic cycle although it does filter nitrate before that.
- I can't find any size recommendations. such as you'll need X size if you feed X amount of cubes per day. A test like that would be very helpful.
I'm still partial to algae scrubbers because I like to physically "see and remove" the waste / algae from the tank but BCBs are an excellent solution. I likely use both on my next tank build. If I build another canister filter I would do the cheap DIY 5 gallon bucket canister filter.
This guy does a good job documenting his BCB test for the first time. Highly recommend reading:
https://www.tropicalfishforums.co.uk...,268722.0.html