the lid was replaced with a new one as was the o-ring and I used Jacks lube. But the whole unit was made out of cheap plastic and it would not seal airtight. Ever since I removed the unit from the pump, my filter has been running perfectly, no more air in the system. I am still using a skimmer basket and a skimmer filter bag in the thru wall skimmer. So I l know I am keeping debris out of the pump.