You started with a whole 1 cup??? Keep a close eye on that pressure to make sure it does not jump up in the next hour.
I just put the DE in the skimmer without adding it to water or such. Measure DE and pour it right in to the skimmer worked for me.
Well that ^^^^ sure is different. Lets start at the beginning:My filter pressure dropped back to 10psi after a few days. I added another round of DE, the pressure did increased right after i added the DE, but dropped down again after a few days. And there is no improvement on the water. I still need to vacuum to waste weekly. So will it be possible that all the DE got pass the filter and into my pool.