30psi?! Please Help

[fredbrussells]

The pressure gage on the top of my Hayward cartridge filter is reading 30psi. I'm really hoping you can help : ) When I turn on the pump the filter housing bulges up like it's ready to pop.

I do not have an algae problem.

I just flushed the pool heater with 1:2 mix of muriatic acid:water. circulated through the heather with a pump for a few hours. water was only a little cloudy from the acid, but still able to see through it and it was not a thick grey color like i would expect if there was a lot of deposits in the heater. then i visually inspected the heat exchanger tubes by looking into the inlet and outlet of the heater. no evidence of a clogged heater.

I installed a new gage and it continues to read at 30psi.

When the pool was brand new 7 years ago, the gage would read around 10 to 15 psi

Please help : )

Here's my set up:
7-year-old pool and equipment
9000 gallons - rectangle 12ft x 28ft x ~4ft
1.5hp Hayward pump - seems to run fine
Hayward cartridge filter - replaced 4 new filters in Dec 2019, cleaned them in June 2020
Aquastar skimmer
A&A Mfg. in-floor cleaning system - seems to work normally
salt chlorine generator - checked it no blockage or calcium build-up
Hayward pool heater H-series 300,000 BTU - yep it's huge for a 9000 gal pool.

[Denniswiseman]

I would suspect that the deposit from the heater has clogged up your filter
Clean your filters again

[Nicole]

Could it be you need new filters again? or there is some kind of hardened salt deposit blocking water flow?.

[Teapot]

You also do not need a 1.5hp pump on a pool that size, .5hp- .75hp would be plenty. You are just needlessly burning up electricity and reducing the effectiveness of your filtration.