High Pressure in the Pool filter

[MDX]

Hi

I am new to owning a pool. We just bought this place and the pool came iwth it.
The filter and pump are of Hayward brand and they were working fine. About 3 weeks ago the filter pressure dropped to under 10 psi. I opened the filter cartridge and cleaned/hosed it. It ran fine for 1 week and then the pressure went up to more than 35 psi. The normal running pressure is 25-30 psi.
Now there is very little suction power.

Any ideas on what i should do to correct this?

Thanks