High sand filter pressure

Mar 14, 2019
12
Adelaide, Australia
I have some high sand filter pressure issues. I've recently moved to this house which has a pool. I believe when I first saw the gauge on the sand filter three months ago it sat about 70kpa (10psi)

For some reason now it is about 100kpa, photo below shows 110kpa as I added some DE to the skimmer

I have replaced the gauge with a new one. I have done a somewhat deep clean of the sand filter (which didnt appear too dirty). Both the above didn't reduce the pressure.

Water is crystal clear, skimmer and pump baskets clean, no air bubbles in pump lid, use a dolphin/maytronics robot to clean to reduce load on sand filter

I've had to drain approx 2500-3000L of water tonight due to heavy rains in the past couple of days and noticed the pressure sat at 65-70kpa when wasting which makes me think theres an issue with the sand causing the excess buildup of pressure

What should or could I try to do from here to lower the pressure?
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Last edited:

woodyp

Mod Squad
TFP Expert
LifeTime Supporter
Apr 17, 2010
10,503
East Texas
70 kpa equals only 10 psi. Why do you think that's high? My sand filter clean pressure is 12 to 14.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
22,053
San Dimas, CA (LA County)
the pressure sat at 65-70kpa when wasting
Stop right there. On waste, the filter is out of the system. It should show zero pressure. If you show pressure on waste, you probably also show pressure when off, which means a bad gauge. And if it goes to zero off but shows pressure on waste, then you have an internal leak on the multiport.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
22,053
San Dimas, CA (LA County)
It's a brand new gauge, both the old one and new gauge one zero when pump turns off. Gauge works

Internal leak meaning rotor/spider gasket is busted?
That would be my guess. Something is interfering with normal operation. You just shouldn't show pressure on waste. Waste is into the multiport and straight out the overflow, bypassing the filter completely. So why does the filter show pressure?
 
Mar 14, 2019
12
Adelaide, Australia
Wo
That would be my guess. Something is interfering with normal operation. You just shouldn't show pressure on waste. Waste is into the multiport and straight out the overflow, bypassing the filter completely. So why does the filter show pressure?
Would there be any residual pressure still since the pump pushing the water somewhere, even if it is to waste? I did a search and cant find anywhere on the net if there should or shouldn't be pressure when wasting water

Also it does leak water out the backwash/waste pipe when it is on the filter function. So theres an issue with the multiport seal either way
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
20,356
Laughlin, NV
Where does your backflush water go? Out a line into the yard? Into the sewer? Unless the waste line is very small, there should be no filter pressure when on backwash/waste.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
20,356
Laughlin, NV
Your signature does not show your pump. An oversized pump for the system can also have high pressure.