25+ PSI Filter Pressure Won’t Come Down

  • Last Post 31 May 2019
mjo217 posted this 26 May 2019

Hi, I have a 36” Hayward ProGrid DE filter. When I opened the pool this year it was INCREDIBLY green and full of algae. However, even after backwashing properly and thoroughly cleaning the grids, the pressure immediately jumps to 25 PSI, before I can even get to the skimmer to add DE. 

Some things to note:

1) There are some but not a ton of air bubbles coming back into the pool while on filter

2) Opening the top air valve on the filter doesn’t relieve any pressure 

3) The jet pressure is incredible while on “recirculate”

4) All gaskets before the pump are in good shape and in proper position. 

5) The pool’s water level is a little high, certainly not too low  


I have absolutely no clue what else to look at. Any ideas?

InyoRob posted this 31 May 2019

The filters can fill up very quickly when the pool is green. My suggestion would be to run the filter on recirculate and add 3-4 times the normal amount of shock. This should kill the algae. If it doesn't, add more shock. Once the algae is dead and the water looks milky, add a product called Floc & Vac. This will force all of the dead algae to fall to the bottom of the pool. Then you can vacuum the debris to waste and bypass the filter. 

At that point, you should be able to get the PSI down and run the filter normally.