The filter bag(s) most likely have a hole or two in them. It could also be the filter bag outlets are not will connected to the manifold allowing DE to get inside the filter.
Scspriggs is on the money - the filters get small holes at the edges - you can use silicon to repair.
Also when re-fitting filters - they must be alined in the slots - not as easy as it sounds - take your time - check work after and before putting together. Good luck.
Answers & Comments
The filter bag(s) most likely have a hole or two in them. It could also be the filter bag outlets are not will connected to the manifold allowing DE to get inside the filter.
Scspriggs is on the money - the filters get small holes at the edges - you can use silicon to repair.
Also when re-fitting filters - they must be alined in the slots - not as easy as it sounds - take your time - check work after and before putting together.
Good luck.