Sand Filter Abnormally High Pressure

RufusT

Well-known member
Apr 16, 2017
85
Choctaw, OK
I'm on year 3 of owning my pool. The firstyear, everything was easy. I followed the advice of the people on this forum and had no issues.

Last year, same thing, for the most part, though it seemed like the water coming from the jets was less powerful than before. I removed my multiport valve and did a "deep clean" with a hose, following directions found on youtube... no real change.

This year, when I opened my pool, I had 25psi almost constantly. I've tried a few things and done a lot of internet research... which lead me to believe I had a bad o-ring in the multiport (leak out the top)... took it to local store for parts and they rebuilt the whole thing for me. Changed the sand while I had it all apart..

No noticeable change... except right after backwash.

If I put to recirculate, it runs around 12psi. Filter runs in the 20pso range.

I've never seen it that high.

Does this sound like an equipment issue? I had started my SLAM, but seems like I have to backwash every 20 minutes or the return jets stop flowing water.

Thoughts?
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Rufus, at this point everything you are stating seems to point to a chemistry issue - algae. You noted that you are indeed in a SLAM right now, so the water must have a heavy organic load at the moment. That will certainly increase the pressure quickly, and when you backwash it lowers for a short time. Then clogs-up again. Perhaps next post, show us your test numbers so we can see what you are working with there. Hopefully you are maintaining the proper FC level based on your CYA? FC/CYA Chart

The only other thing to answer .... is your gauge working properly? Does the PSI needle fall to zero when you turn the system off?
 
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splashpad

Bronze Supporter
Aug 2, 2017
1,994
SE Kansas!
...
If I put to recirculate, it runs around 12psi. Filter runs in the 20pso range.
I've never seen it that high.
..
Same pump?
...Does this sound like an equipment issue? I had started my SLAM, but seems like I have to backwash every 20 minutes or the return jets stop flowing water.
Sounds like it's working to clear the algae
 
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Mendy48

Bronze Supporter
Apr 27, 2018
737
Midland, MI
I agree that there could be a lot of algae in your pool right, thus increasing your psi. How does your water look? I see that you have a sand filter. You may want to vacuum to waste to avoid clogging up your filter if your pool is really dirty....while at the same time continue vacuuming and brushing your pool during the SLAM process.

I’m also curious if your psi falls to zero when your pump is off...
 
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RufusT

Well-known member
Apr 16, 2017
85
Choctaw, OK
Brand new gauge. Zeros out when off. There is a reasonable amount ...if algae/ dirt, but no more than previous years.

Did a few more things this evening: shut off fuller system completely. Befoee shut off, 26psi... 15 minutes later, turned back on and was 16psi. Let it filtering and was 22 psi. Chlorine was 3ppm. I had brought it up to 11 large this morning when m I tested. Added more bleach broke coming in for the night.

Fc: 3
Ph: 7.2
Ta: 50
Ch: did not measure (not concerned during slam)
Cya: 0-20 (doesn't register)

This is the same pump that has operated in the 12-14psi range for two years.. is it normal for an increase?

...if this is not an alarming range, I'm ok continuing on the path... just hoping to get some pointers of what else it could be, ...if anything.
 

Mendy48

Bronze Supporter
Apr 27, 2018
737
Midland, MI
Interesting.... I’m not sure what else it could be other than organics/algae/dirt pushing your psi upwards. Did you try vacuuming to waste to see if this would help? If this isn’t algae, I’ll let an expert chime in here shortly. I’m curious to see what else this could be.

Also, With a CYA that low, you may want to bring that up to a 30 and SLAM at an FC level of 12 and try to maintain it there...test you FC frequently and make sure it doesn’t fall below 12. What FC range are you currently SLAMing your pool at?
 
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Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Fc: 3
Ph: 7.2
Ta: 50
Ch: did not measure (not concerned during slam)
Cya: 0-20 (doesn't register)
I think your best course of action at the moment is to perform a SLAM Process. Don't cut any corners, and make sure you stick with it until you pass all 3 criteria. Your last numbers show two important problems.... one, the FC is nowhere close to SLAM level, so any algae isn't being eliminated; two, your CYA is low which is leaving the chlorine susceptible to the sun defeating your effort. So at this point, before trying anything else or worrying about any other potential system issues, I would resolve the chemistry portion. It's generally the cheapest thing first, and you really do need the water algae-free. Algae, even in its clear stage, has a way of disrupting pool operations and causing multiple problems.
 
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RufusT

Well-known member
Apr 16, 2017
85
Choctaw, OK
Ok... update in case others have a similar issue. I am still clearing the pool, though I'm at the tail end. I have not conducted the OCL test, as I'm still cleaning dirt from the pool. Leaves are out, except for new ones that get introduced. . But this was not my problem... I don't think.

I believe there are multiple issues that were all contributing to my issues, as each reduced my pressure a little.

1. Old Sand - for no more than it costs, this should be first check.
2. Located small leak in joint where backwash pipe is connected. Resealing with silicone eliminates some noise and decreased pressure by nearly 4psi.
3. Sound is still loud inside the multiport valve. I suspect there is an air leak in the assembly where the key assembly joins the body of the valve. Once i get the money I'll replace that and should be back to normal.