impossible to solve DE on pool bottom

[tomj1]

I would tend to agree but there were no issues for the first few years we had the pool and the specs of the filter: design flow rate 96gpm max pressure 50 psi (does not specify if this is max working pressure of the tank or max pressure on the dirty side of the filter) I would expect it to be the former. I've never seen the filter pressure exceed 25psi The pump specs: flow @ 20' of head 83gpm, from the hayward chart at 10' of head about 90gpm, so it would appear the pump and filter are compatible. I do know after this experience if I DO replace the filter there is no way that I would consider any filter that uses any sort of granular material. I'm considering a pentair clean and clear plus 520sq ft cartridge filter 520 sq ft which will handle 150gpm (nsf) with a 72000 gal 8 hour turnover.The pool gets very little use, and there isnt a tree within 200 ft, but it is open all year. There is again, after the last cleaning, a good bit of DE on the bottom after my last vac yesterday. I'll be vacuuming again to make sure this was not just material in suspension; after that the only thing I can do is to install a temporary bypass after the pump to reduce the flow/pressure through the filter as an experiment, it would be helpful is some DE expert can tell me what the preferred pressures would be for my system for the following:

A:clean grids with zero DE present
B:filter fully charged with new DE
Cressure at what should be considered ready for cleaning

If I have that info I can compare to my current situation and if I add a temporary bypass adjust pressure to what is recommended.

thanks
tom

[tomj1]

Rather than doing a temp bypass might be easier to try to swap out the impeller as you mentioned above. Do I just order the impeller from the next smaller pump, or are additional parts required? (I've never had it apart...
)

tom