Thanks for all the replys, kind words, and questions!
I'll have to take some system pictures so that I can better explain how the system operates.
In a nutshell, Each tank operates on it's own sponge filter plus two identical central systems. Half the room is set up for breeding discus (soft water) and the other half is simply tap water for adults, juvies and grow out. I can pull any tank off the central system at any time for any reason.
The room is centrally heated with a gas heater. Room temp is typically about 90f and tank temps are around 86f. The central systems are 125 gallon glass tank sumps with 100 micron filter socks and 4 layers of matal bio media. Nothing too fancy. The returns are 1.5" PVC powered by two Sweetwater High Efficiency pumps. These pumps move 45 gpm through this system, that's 2700 gallons per hour. These pumps do all of this using only 170 watts of power. They are fantastic!
Soon to come, I'll be adding ozone to these central systems to aid in water purification. I just got the reactor built and have to get everything plumbed.
More pics of the setup and fish to follow!
Best wishes!