Gradually losing pressure

[gmercer9]

Pool starts fine with strong pressure, which slowly drops over a few hours. It never loses prime. There are no air bubbles in the filter lid. If I turn it off, wait a few minutes and turn it back on, pressure goes back up and gradually drops again. If I turn it off and open the air valve, there is air that escapes. It will prime back up at full pressure with no problem.

Out of an abundance of caution, I replaced the filter cartridges with new ones and it did not help.

Any ideas??

 

[Jimrahbe]

9,

The number one cause of the problem you have described is algae, whether you can see it or not.

Show us a pic of your pool water.

Thanks,

Jim R.

 

[gmercer9]

 

[gmercer9]

Thanks. Posted pic- waiting for moderator to approve.

Assuming algae, how do you address?