DE filter pressure goes high very fast

I'm having some issues with my DE filter. When I clean and recharge it with the manufacturers recommended amount of DE (4.5lbs. For my 36sqft filter) it works great for about an hour. Then the pressure starts to climb up 20 psi in a few more mins. Then there is little to no suction. What am I doing wrong?

I mix it in a bucket and pour it into the skimmer slowly as I should, but it still goes up.

I'm am soooo frustrated. And my pool keeps turning green.

Help!

Thanks

Hi and welcome to the Pool Forum! Do you have algae in the pool? Live algae will clog a DE filter fast!