Air Leak?

[cazten]

New pool owner here. Watched tutorials on cleaning my cartridge filters and first step was to open the top air bleeder and the botton drain plug on the filter housing to drain the housing of water.

Im already stuck at step one! When I open the bottom drain (it has a hose bib valve on it) air actually sucks into the housing! Even with the top bleeder open the entire housing seems to be under suction pressure. I can hear the air bubbling into the housing but nothing leaks back out. The suction is pretty weak as I can plug it easily with my finger of the hose bib valve but obviously enough that it doesnt actually drain....


Thoughts? I was worried to leave it on for more than a few seconds at a time so I have attempted to leave it wide open.