Yes I did say it was only my opinion and it was because a 20 gallon is just not worth much in the reef world anyways. I know alot of people have nano-reefs and they do fine, but most fish simply need more growing space than that. If you are going to spend all that money to drill, setup a sump, and buy lighting for reef life, it would make more sense(in the long run) to go ahead and get a pre-drilled tank in the 30 plus gallon range and use the 20 for the sump. I always state that my opinions are my own and that other people are entitled to take it or leave it. By the way, Firsttimer89, did you check out that website thread that I put in my original answer. We have already built a prototype and added a hole in the top of the return line just above the water in the tank. When you kill the power the syphon breaks and the tank only drains till it is below the holes in the overflow. The hoses in the overflow never break syphon, so when the power comes back on, the system starts back up with no overflowing of the tank or the sump.