impossible to solve DE on pool bottom

[CarlD]

Hi,
I'm not the DE expert but it sounds like your pump is putting out too many PSI for your filter. IF you can establish that is the case, you can downsize the impeller on the pump to LOWER your pressure.
If you decide to change filters, consider going to a sand filter. A 300# filter should be fine for your setup, and there are lots of inexpensive tricks to have them perform as well as a DE or cart filters. Much easier to maintain, too. Cleaning a cart is a major pain in the neck.

[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