As for my back chambers I took out the crap return pump, and put in a maxijet 900 in its place, that along with a koralia 1 and I have plenty of flow. My first chamber(on the right if you are looking at the tank) has purigen and chemipure. 2nd chamber has the false floor removed and the bioballs got taken out. I have a wad of chaeto that is slowly growing, it is also filled with pods I have a 10 watt submersible light shoved down into the middle of it. In chamber 3, the return pump, a bag of rowaphos and a 50 watt heater. Everything is working well, knock on wood, all my parameters are in check and very steady. I run my fuge light on the opposite schedule of my actinics, this way my ph stays steady and the chaeto gets about 13 hours of light.
Just tested:
Specific Gravity...1.026
PH...8.1
Nitrite...0
Nitrate... around 5
Ammonia...0
Phosphate...0
Alkalinity...11dkh