I have another question. I was thinking of adding two 1400 GPH Hydor Koralia Evolutions powerheads to the tank, one at each end. They produce about 4' of current so this would be the best choice. I was wondering though are powerheads a must? I'd get these two if they are b/c they sell them for cheap at work but would this be to much OR to little flow of water? I don't want it to stire up the sand etc.... and make the tank a mess.