HELP! Hayward Cartridge Filter

[momof2grlz]

Hi, everyone. I'm a new pool owner. We have a 12'x 25' IG fiberglass with Hayward Star Clear Plus cartridge filter, Hayward Max-Flo 1 HP pump and Reliance SWG.

With the cartridge installed, the filter pressure jumps to 28 p.s.i., there's very little suction at the skimmer (not enough to vacuum), the SWG panel shows "Insufficient Water Flow, and we are getting constant air bubbles out of the returns into the pool.

If we remove the cartridge, the filter pressure drops to 10 p.s.i., great suction at the skimmer, the SWG operates fine and no air bubbles. I"ve cleaned the cartridge a half dozen times, so I know it's not dirty.

Any suggestions on why the cartridge being installed would cause everthing to go haywire? I've removed the cartridge for now so the SWG can operate, but I know it will have to go back in - and then all of the problems will return.

Any help will be appreciated.

Chris