Careful if ur looking at ATB, they size their skimmers kinda differently. Bubble King says my skimmer is rated for 350 gallons, ATBs 350g rated skimmer is like half the size of my skimmer. Either bubble King under rates their skimmers, or ATB over rates theirs. If u want a BK250, I would look at the atb 12.5. Not bashing ATB, just don't agree with their skimmer rating.