I have the 2,500 GPH Intex Cartridge Filter Pump with my Intex metal frame pool.

I noticed when I open pump to clean cartridge, that it's only 1/2 way filled with water (at most) lately. Sure, it's fine if I turn the air release valve on top and bleed the air out. Then about 1/2 hr. later I check it and the water level's dropped. I put some vaseline on the "O-Ring" on the inside cover and still no luck.

It doesn't look clogged and appears to be sucking the water fine through the skimmer and blowing out fine through the discharge.

Any help on this is greatly appreciated!

Thank you!