I know this has probably been addressed before but I have been away from this forum for a while.

I have a Pentair FNS plus 48 DE filter system. lsat year I was getting DE on the bottom at the end of the season. I didn't worry about it to much until I backed washed for the winter(my pool runs year round in San Antonio) due to pressure. When I backed washed my pressure was still up so I tore apart the filter to do an extensive cleaning on it.

While doing so I found the DE problem was my Internal Air Bleed Assy. was completely disinigrated so I replaced it with a new one part #190091 which is a screen type different form the one before. I also cleaned my filters look wich looked OK until I uncovered the pool for the season and had DE on the bottom so I vacummed and it kept coming back but notas heavy.

I spoke to my local pool store and the said to check the grids real good and for cracks in the manifold. While doing the cleaning I inspected everthing and could not find anythin wrong with the grids or manifold. So I pur everything back together replaced the o-ring on the tube to the manifold and put everything back together. I also look at the multi port valve gasket which aslo seamed to be OK.

I am still getting DE into the pool and do not know what else I can do. My wife thinks if I keep vacumming what comes in becuase of the stirring and vacumming it will eventially go away, but I do not think so because it should be captured in the filters and not be reurning. I feel it may be the new screen type breather but it is a factory replacement. Has anyone else had this issue after replacing the Air Bleed Assy. or have any ideas on what is causing the DE to come into the pool??