High PSI, low flow, help needed!


Jun 5, 2019
Hi all - long-time lurker, first post.

I have a 20,000-gallon in-ground pool. Starting a couple weeks ago, my pressure jumped up to 32psi and the flow from the skimmers and drain crawled to probably half. I have disassembled the filter and run it without the cartridges and got the same reading. I then took apart the pump (WhisperFlo) and checked the impeller - all good there.

Skimmer baskets are perfectly clean. The pump pot is clear and there are zero bubbles when it's running. Both valves from skimmer and drain lines are functioning. Pressure indicator drops to zero when not running.

What else am I missing? Only other thing I can fathom is a blockage to the returns.

Thank you!


Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

Most of the time when the pressure goes up and your flow goes down, it is a clogged filter, but since you have the same issue with the cartridges removed, then something else must be in the return path.. Basically the filter PSI is the amount of effort it takes to force water through the filter and the return path back to the pool..

What else is in that return plumbing for your pool?

Pictures of your equipment pad from a couple of different angles would let us "see" more than a thousand words.. :)


Jim R.