I cant leave it on!!!! It overflows to the drain within 4 or 5 mins....I would fill up a 5 gallon bucket by morning!!! Or even worse...the entire tank!!!!
Its a 46 gallon bowfront with 3 damsels, 2 clowns, a couple snails, a hermit, and a few hitchhikers. Also have 20lbs live sand, 30lbs...