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Thread: Pool pump/filter flow problems

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    Pool pump/filter flow problems

    I moved into a house last year that has an in ground pool, the first pool I've owned so I am new to pool care and feeding. The problem I am experiencing is causing the pressure on the gauge attached to the filter to increase from 9 psi to 20 psi sometimes over a few hours and sometimes in a matter of minutes, once the pressure rises there is no flow from the returns, the SWG also displays the message "no flow". Since I opened the pool 2 weeks ago I initially assumed it was due to the filter doing it's job and I would backwash it and the pressure would drop back down to 9 psi and everything was fine again. This continued for the most of the week and didn't seem to be improving even though the water looks fairly clear. I was backwashing the pool about every 2 hours which seemed to me to be excessive so I started looking for other causes.

    What I have stumbled upon has me baffled - if I simply turn off the pump for 10-15 seconds the pressure will drop from 20 psi to 9 just as it does when I backwash it. This led me to believe there was some sort of obstruction in the plumbing so I disassembled the plumbing around the filter and pump checked the lines and I didn't find anything. I ran water backwards through the filter valve to see if there was something trapped in there - nothing. The pool has 2 returns which are connected via one valve to the outlet of the filter and fountains that are on a separate valve and when the flow drops both are affected which would indicate to me it's not something underground between the filter and the returns.

    At this point I am at a loss for possible solutions. I didn't have any issues with the pool like this last year. I installed the SWG in July of last year about 1/2 way through the season. I think my next logical step would be to disassemble the 6 way valve to look for something that is malfunctioning or clogged but I don't know the manufacturer of the pump or filter and I don't know where I would get replacement parts for it if I were to break something during disassembly, it still sort of works and I could make it worse.

    I am looking for suggestions or if anyone has experienced an issue similar to this in the past.
    24,000 gal 18 x 38 vinyl, 1.5 HP pump, 24" diameter sand filter, Hayward ProLogic w/T-15

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    Re: Pool pump/filter flow problems

    Welcome to the forum.

    I have not read your post thoroughly but I see one issue.....with the pump off, regardless of any blockage, your psi should drop to ZERO. A bad gauge is the first issue and needs to be replaced.

    oops! are you saying it returns to nine when you reenergize the pump?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Pool pump/filter flow problems

    Thanks, I have found many answers on these forums but this one has me baffled!

    Yes - when I switch the pump off it drops to zero.

    It will be at at 20 psi - I switch the pump off - pressure drops to 0 psi - I wait 15 seconds - I switch the pump back on - pressure back to 9 psi.
    24,000 gal 18 x 38 vinyl, 1.5 HP pump, 24" diameter sand filter, Hayward ProLogic w/T-15

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    Smykowski's Avatar
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    Re: Pool pump/filter flow problems

    Can you post a full set of test results? Sometimes what appears to be an equipment problem turns out to be a chemistry problem.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
    The most important article on this site - The ABCs of Pool Water Chemistry

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    Re: Pool pump/filter flow problems

    I have run out of the reagents for testing CYA from repeatedly testing over the past 2 weeks, it was at 70 the last time I tested it but since then I've backwashed out around 3000 gallons of water and refilled due to this issue. FC was 11 3 days ago so I reduced the SWG to 50% today it was 7. I have added salt due to the replaced water but no CYA.

    FC - 7
    PH - 7.5
    CC - 1
    TA - 90
    CYA - ?? I'd assume less than 70
    Salt - 3000 according to the SWG, I don't currently have a test kit to double check this result.
    24,000 gal 18 x 38 vinyl, 1.5 HP pump, 24" diameter sand filter, Hayward ProLogic w/T-15

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    Re: Pool pump/filter flow problems

    Besides the multiport valve, if you have any check valves, make sure they are in working order.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Pool pump/filter flow problems

    I checked the valves on the returns earlier this week and they seem to be ok, they are basic ball valves that don't seem to be serviceable in any fashion. Tonight I installed a gauge on the outlet side of the filter to see if there's some sort of obstruction in the return piping I couldn't find. It's currently at 6 psi while the filter gauge reads 10.
    24,000 gal 18 x 38 vinyl, 1.5 HP pump, 24" diameter sand filter, Hayward ProLogic w/T-15

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    Re: Pool pump/filter flow problems

    Maybe you could try setting your filter to recirculate for a time. If the issue goes away you will know the problem is in the filter. If you still have the issue then the problem is in the plumbing.

    What does the pressure guage after the filter read when the filter guage jumps to 20 psig?
    Cheers, Peter
    20,000 gal, 52'x17' kidney shaped IG, Pebble Tec, IntelliPro P6E6VS4H-209L pump. Intellichlor IC40 SWG.
    300 sf Sta-Rite System 3 cartridge filter. Poolvergnuegen 4-wheel suction pool cleaner. TF-100 test kit.

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    Re: Pool pump/filter flow problems

    It happened again this morning the gauge on the filter started out at 9 psi and after the pump was running for about 1 hour, the output pressure gauge was at 0 psi while the filter gauge was 20 psi. I would suspect this would rule out an obstruction in the return plumbing. The water is clear but as I've seen other posts there could be something lurking in pool that I can't see, if I run it on recirculate is there a potential of damaging the SWG cell?
    24,000 gal 18 x 38 vinyl, 1.5 HP pump, 24" diameter sand filter, Hayward ProLogic w/T-15

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    Re: Pool pump/filter flow problems

    It looks like something is blocking the flow thru your filter. It may be that algae or other debris are blinding off the filter media, or you have a problem with the multiport valve.

    Running the filter on recirculate allows the water to bypass the filter, the SWG should be fine.
    Cheers, Peter
    20,000 gal, 52'x17' kidney shaped IG, Pebble Tec, IntelliPro P6E6VS4H-209L pump. Intellichlor IC40 SWG.
    300 sf Sta-Rite System 3 cartridge filter. Poolvergnuegen 4-wheel suction pool cleaner. TF-100 test kit.

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    Re: Pool pump/filter flow problems

    I ran the pump on recirculate for about 4 hours today and the problem did not occur. I was able to test CYA today and it's at 20, CC went up to 2 since the last time I tested it 2 days ago. At this point it all seems to point to something clogging the filter media even though I can't see it in the pool or when I backwash - possibly something that floats up off the surface when the pump is switched off resulting in the pressure drop from turning the pump off and on again.

    Thanks for the help.
    24,000 gal 18 x 38 vinyl, 1.5 HP pump, 24" diameter sand filter, Hayward ProLogic w/T-15

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    Re: Pool pump/filter flow problems

    Just a thought, here in Seattle the cotton wood trees have been going off, I don't know if you have cotton wood trees in NJ, if you don't, think of a dandelion the size of a tree, blowing the fluff into the pool, clogs my sand filter in no time.

    I put skimmer socks in, think of a nylon that goes in your skimmer basket to keep stuff out of your filter.

    http://www.amazon.com/Pool-Filter-Sa.../dp/B00373PFT8



    The skimmers may get clogged up but the filter stays clean & still pulls water from the bottom & keeps the water coming out of the returns, take the skimmer socks off & rinse them clean with the hose & replace.
    I consider myself very lucky I found this site before the pool store found me-pool owner since Nov 2008- Stunningly clear 17,000 gal fiberglass pool, thanks to this site, installed in 1982-24" 3.1sq. ft sta-rite sand filter, 1 hp - 2 speed wisperflo pump-WFDS-4

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    Re: Pool pump/filter flow problems

    No cotton wood trees here but tons of Oak, Maple and Pine that all drop pollen with associated debris. I decided to slam the pool starting last night. Went to the 24 hour store to buy bleach at midnight, they only had 7 gallons - received an inquiry from the cashier about the somewhat odd purchase. This morning I went to the local pool store for more reagents for testing and they had 5 gal refillable containers of liquid chlorine on sale for $10 with a deposit for the container, picked up 10 gallons - no strange looks from the cashier. CYA is now 60, FC is 25 CC is 2.6, I was probably on the brink of disaster. thanks all for pointing me in a different direction than equipment.
    24,000 gal 18 x 38 vinyl, 1.5 HP pump, 24" diameter sand filter, Hayward ProLogic w/T-15

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    Re: Pool pump/filter flow problems

    Sounds to me like you have a low level algae bloom and dead algae is clogging your filter. Nothing clogs a filter faster than algae. I would recommend SLAMing Your Pool.
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    Re: Pool pump/filter flow problems

    Sorry I didn't get back to this thread.

    I think the issue is this......you are rapidly accumulating debris in your filter that quickly brings the psi to 15. Then when you shut the pump off, that abrupt "bounce" in your water flow jostles the debris in your filter and dislodges it somewhat......allowing your psi to go down to nine when you restart the pump.

    The solution is like pooldv says above.....time to SLAM and you will need to backwash a lot at first.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Pool pump/filter flow problems

    Yes, backwash every time the pressure rises 20-25% over clean pressure.
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    Re: Pool pump/filter flow problems

    I began the SLAM process on the pool 2 nights ago and since then I've been able to run the filter for 8-10 hours between backwashing which before was anywhere from 5 minutes to 2 hours. The pool now has a slight brown tint to it and there are some dead soldiers on the bottom of the pool where the slope of the deep end meets the hopper. Keeping the FC up to 24 has been a challenge needing to add liquid chlorine every couple hours and now the PH keeps rising up to 8. Is it normal for the PH to rise during this process?

    I'm sure there's something in the pool based on the testing results but what has me in disbelief is that before I started the process I was able to read the the lettering that is molded into the drains on the bottom of the pool, the water was clear.
    24,000 gal 18 x 38 vinyl, 1.5 HP pump, 24" diameter sand filter, Hayward ProLogic w/T-15

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    Mod Squad pooldv's Avatar
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    Re: Pool pump/filter flow problems

    You just caught it early, a few more days and it would be cloudy, another few days green and then swamp. Algae grows aggressively and dead algae clogs a filter like nobody's business.
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    Re: Pool pump/filter flow problems

    . Is it normal for the PH to rise during this process?
    Ignore that test. the pH test gives a false high in the presence of high chlorine (over 10 ppm FC)
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Pool pump/filter flow problems

    Thanks, I will focus on the chlorine readings for now. The SLAM process has been going well, it's now at a point where over the last 3 hour period (6pm to 9pm) the FC dropped by 2 from 24 to 22.

    Now my new question - While backwashing throughout the day I noticed I never seemed to get dirty water in the sight glass of the filter so I decided to deep clean the filter with a hose. This seemed to produce more visibly dirty water than backwashing alone which I expected. What I was surprised to learn is that there is only about 1.5 to 2 inches of sand over the laterals which seemed thin to me. The filter has no brand name or model number on it but there is a sticker which lists different models and the amount of sand they require. d400, d500, d600 - the outside of the filter measures 23 7/8" which assuming the model number is the diameter in MM would indicate the model would be d600 which is says requires 300 pounds of sand. Using a hanging scale the entire filter vessel minus the multiport valve with sand (I drained the water but the sand was still wet) weighed 210 pounds.

    I'm making a fairly large assumption that the d600 indicates the diameter of the filter which leads to my question - typically how many inches of sand would you normally expect to have above the laterals, and does 300 pounds of sand seem typical for a 24" diameter filter?
    24,000 gal 18 x 38 vinyl, 1.5 HP pump, 24" diameter sand filter, Hayward ProLogic w/T-15

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