gman52 this is an interesting point, and in fact the reason I decided to use cc on the 200 gallon...previously I had sand in the 55 and had nothing but trouble...However, in all fairness in the 55 gallon days, I had an inadequate skimmer, no uv, probably an inadequate filter as well, and was not using r/o water...so there was so much wrong, that you really couldn't single out one thing to blame. I think if you use sand, the point is not to clean it and have enough inverts and clean up crew to manage it....but with cc I can feed the fish even up to three times a day and maintain the tank, because like you say, i can vacume the cc.