can u c the pic at d bottom. there's a red knob. at the outlet there's a pvc that i cut b4 putting in sump. i put glue to stick the pvc to the outlet so that i can put it outside of sump then my parents complain that the place was messy so i cut the pvc and put the skimmer in the sump.. previously it was outside too. Seriously i have no choice... thats the story..