I've got a 33 gallon, with just those glass bead rocks covering it (I needed probably 15 bags of them, it's expensive gravel, lol). My 7.5" pleco cleans it pretty darn good, but regardless, I now clean it once a day. I take about 5 minutes from start to finish, and clear about 5% of the water out, and replace it with clean water. Inside there, I've got mollies, swordtails, guppies, 2 neon tetras and my 7.5" pleco, who will be moved to a 150 gallon in 2 weeks (he will get big in there!), and I'll get a new baby pleco to replace him in the 33. I actually really love plecos. They are one of my favorite freshwater fish. probably a tie with arowana for first! wish I could breed them, but I hear it's practically unheard of.