DE filter and variable speed pump

PoolFunYikes

Gold Supporter
May 19, 2020
24
New Hampshire
I have a new variable speed Hayward Superpump and new FNS plus DE filter. I’m seeing what I believe is DE settling in the pool bottom and curious if the low running speed of the variable pump has caused some issue that makes DE eventually return to the pool. I can feel it and it has a grainy texture like DE. I was very careful when charging to make a slurry of only 3.5 lbs by weight (weighed it) and have pump at high speed for about 30 min while doing it. A few weeks in, there was DE on the floor which I vacuumed it up with MP valve on filter but it returned within a week.

I previously had and issue with my single speed pump and old filter (same 36ftsq size) which was caused by too much DE. Is there a possibility of continuous operation at low speed (1700rpm) causing the DE to slough off the grids or leak through the grids?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
21,219
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Post pics of your new FNS filter and the MPV. Did you get the proper MPV for your new filter?

Running your pump at low RPM should not affect your DE filter.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
19,841
Bedford, TX
Yikes,

I have two pools with DE filters. Both have IntelliFlo VS pumps running at about 1200 rpm, and I have never had DE get into the pool.. Well, unless it was my fault. :mrgreen:

Something may be wrong, but it is not because your pump is running at too low of a speed.

Thanks,

Jim R.
 
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PoolFunYikes

Gold Supporter
May 19, 2020
24
New Hampshire
Post pics of your new FNS filter and the MPV. Did you get the proper MPV for your new filter?

Running your pump at low RPM should not affect your DE filter.




Thanks for the ideas. Attached are photos of the new filter, original Pentair MPV which fit nicely with fresh union o rings. I replaced the spider gasket last year.
Tonight I vacuumed a coating off the floor again and checked my pressure at max prime speed 3450 rpm to compare to a recording I took after I originally fed in the slurry last month. It is 14.5 psi, only 0.5 psi higher than it was when I charged it. I’ll watch it tomorrow morning when the pump starts to see if I can see if it’s associated with startup.