FSM;1795649; said:You've got really weird dividers in there. The water level will be at the top of the highest one, at least until it gets to the pump section. Therefore, the way you have the media divided is pointless.
tank125;1795663; said:--Since your bio chambers will be completely submerged, the substrat pro is a good idea. bio balls don't work the same under water.
--Your final wall needs to be a lot shorter, other wise it defeats the purpose of the two walls prior. what you are trying to achieve is no bubbles in the pump section, so keep the first 2 of the 3 and make the third like 10cm tall or so.