Filter PSI steadily going down


May 17, 2020
Long Valley NJ
So more of a mystery I’m trying to understand then a problem I’m trying to fix.

the PSI of my DE filter has steadily gone down from about 13 to about 7-8.

However, flow is super issues at all. Skimmers (2) is not blocked up and very strong suction there too. MaIn drain also strong.

the pool is SUPER clean and SUPEclear.

I did do a 4-5 day SLAM 3 weeks ago due to a bit of cloudiness but it cleared up. I thought I would need to backwash after, thinking a lot of dead would be in filter. But on the contrary...PSI have slowly went down since.

my pool generally stays clean due to open area where located and gets direct sun from 8:30am - 5pm.

temps have been mostly low 80s during day and low 70s at night. I keep solar cover on at night and sometimes day when we don’t swim.

is it possible that keeping my FC at or above right level has made algae “disintegrate” in filter slowly hence releasing some pressure? :)

i’m not complaining because my pool is super clear but just wondering.

I’ve kept my at 6 or above throughout. Been losing no more than .5 FC ppm over night.

CYA 45
FC 6 - 8
CC 0
ph 7.5
TA 110


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
No heater?

What model and size DE filter?

What is the PSI after you backwash before you add DE? What is the PSI after clean DE is added?
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