35 gallons, it's have been running for 2 years, 30lbs of LR, 10lb of base rock, 1 clarkii clown, 5 damsels, I changed the crush coral bed to a sand bed last week, and I can see poop because the sand bed is so white ..... when I say the tank is full of poop I was exaggerated, the sand bed is have less poop now cause I put in the extra power head that I have so some of the poop go into the protein skimmer and got pull out.. But there is still poop...