I used them back in the 90's,still using them until now. I just cant get enough of it. The best skimmer IME. Use the right pump for it the performance is endless, sometimes they put too much bioballs at the factory or vice versa it would not put out alot of frothy foam,I like it thick scummy blk. skimmate. W/ this skimmer U can skim wet or dry w/ a little turn of the gate valve. A little pricy but worth every penny.