Well, you are one of the few! I just had gravel and worms. The fish were all fairly small. If I recall correctly, I had 30-40 small goldfish in a 10 gallon tank. They definitely produced TONS of ammonia, but the system converted it EXTREMELY rapidly. I was so impressed. The floaty type solids were sucked up by the pump and typically got left in the growbed above the tank. I did have the water aerated with a bubbler at the time as I did not know any better. I think I had the bubbler in the gravel, but that was just to keep it weighed down as it tended to float otherwise. This was not needed though and didn't do anything extra for the worms being in the gravel.Originally Posted by chrisfoerst