There used to be a guy in Michigan, I believe calling himself Mr. 5000 that had a huge tank (5000 gallons) in his basement. On his website, which is no longer up was a pic of him with snorkel on cleaning algea in the tank. He built it with concrete back and sides and had a 1 or 2 inch thick viewing panel in front. He had like two, 200 gallon sumps and numerous 400 watt (maybe 1000 watt? I forget) MH lighting it up. The problem he ran into was an insane amount of evaporation, like over 100 gallons a day and it was rotting out the floorboards of his house above the tank. On the plus side, he never got hassled from the Tang Police!