Maybe 8 feet? Four from basement to floor, four from floor to tank top..?
Cully, to answer your question... Yes, at first the tank was a holy mess. But I vacuum the sand once a month or so, and the longer he's been in there, the cleaner the tank and water has stayed. I also change out my carbon more often.
After watching some videos that Jake Adams posted with one of the chief chemists from Red Sea, I started using their carbon. My water is absolutely crystal clear right now. Clearer even than when I used ROX .08