Yesterday, I backflushed my Pentair FNS Plus 48 for the first time (first for me), after I noticed that the water has become a little cloudy (I did not have a starting pressure measurement for the filter, as I just started to take care of the pool by myself.) I followed the instructions and everything went well until... I put ~5lb of DE powder into the skimmer (slowly) and noticed that DE is shooting back into the pool. The water became even more cloudy and the bottom has a lot of DE powder now.
I have a technician coming tomorrow, as my first assumption was that the grid(s) failed. However, I noticed now, 24 hours after he backflush that the water is much clearer.
Any idea why the DE came back? Can it be a one-time issue? Should I wait with the technician and see if the water is looking better tomorrow?