Went to the 3 pool stores to pick up DE. They didn't have any, but had an "equivalent" thats supposedly better than DE.

I tried it on the weekend, waiting only about 5 minutes, before reading the pressure gauge. Pressure rose very little, so I put in another cup, 3 in total.

Later in evening, checked pressure gauge and it was up 8 lbs.
So I had to backwash it away and start over.

How long should to wait for the pressure to increase?