I done this about 6 years ago on a 240 gal. tank. Sure it looks cool, but it don't vac wastes, and don't really change enough water at once to do much good really. It just mixes about 40 or 50 gals. of clean water over 24 hours to the rest of the dirty water. I used it for about six months, and unhooked it. My water quality actually improved when I started changing water the old fashioned way again.