Algaecide and Pressure Increase

We just replaced our DE filters 3 weeks ago, had an algae issue. So, I put in the algaecide this morning and within an hour the pressure shot up from 12 to 20, and the spa jets are not flowing. Is this normal? Should I let it cycle through or do a backwash?

When you say you replaced your DE filter ----- do you mean bought a new DE filter? Added more DE to the existing filter? Bought a sand filter instead?

If you are getting no flow, then that is not normal.