Running AGP cartridge filter w/o strainer basket

[PoolDoc]

I'm not at all sure what you've done. On every pool pump I've ever seen, the strainer basket is internal to the pump wet end, and has nothing to do with whether your pump sucks air, unless:

1. it's the wrong size, OR
2. it's inserted incorrectly,

causing the pump lid to fail to close fully.

[aylad]

Or--the gasket around the top needs to be replaced....

[Dutch]

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.