RBC = Rotating Biological Contactor. It is basically a water wheel with tons of surface area for bacteria to grow on. If you've ever seen those biowheels on aquarium filters, it's essentially the same thing, just much bigger. It spins slowly in the water, "detoxifying" the water while it does. Since much of it is actually out of the water during the spinning, the bacteria get the benefit of O2 from the air, and then get "dunked" back into the water to do their thing... over and over. It's actually a lot more complex than that, but this is the general idea. They aren't terribly hard to build... I mean Cecil recently built one, so how hard could it possibly be? Just kidding Cecil! Hopefully he'll chime in on this. He's done a lot of work on his RAS this Winter, so is a great resource.

Tilapia tolerate a pretty wide ph range. 7.0 is a good place to try for though. Honestly, I haven't tested ph in a very long time in any of my tanks because things have just worked out fine as is.

12 ac pond in NW Missouri. 28' max depth at full pool. Fish Present: LMB, BG, RES, YP, CC, WB, HSB, WE, BCP, WCP, GSH.