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Thread: Water Pressure

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    Water Pressure

    Just for full disclosure, we got our pool used. It was put up new for 2010 season, but HOA made the original owner take it down. They used it for that season while appealing, etc just to be able to use it. I don't know if it was taken down in the fall or spring of 2011. I got it last summer and everything sat till this spring. After I had everything hooked up, the first thing I did was backwash for several minutes. The pressure gauge was broken so I replaced it. The new gauge has the water pressure at 17 PSI consistently since I put it in. Last weekend vacuuming a lot of **** after 2 storms, the pressure didn't really go up, I expected it to. After vacuuming again and backwashing yesterday, the pressure still neither rose nor fell. Is it just I have a really clean pool? Or maybe I am not backwashing/rinsing well enough? How much of a change in pressure should I expect before having to backwash?
    27' Round Might Sun AG Pool 18000 Gallon Intex Krystal Clear SWG Hayward Pump/Filter on a Timer

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    Mod Squad Bama Rambler's Avatar
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    Re: Water Pressure

    That's a small filter for that pool so that's why the pressure is high. I'd pay attention to the flow out the return to gauge when to backwash. When there's a noticable difference I'd backwash.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Water Pressure

    Just out of curiosity, what size filter should I have for this pool? According to Hayward's specs on the filter, it can handle the GPH rating on the pump plus a little more.
    27' Round Might Sun AG Pool 18000 Gallon Intex Krystal Clear SWG Hayward Pump/Filter on a Timer

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    Re: Water Pressure

    Oh, with the pressure already that high, I got a bag of DE today intending to add some to the filter. Should I be worried about the slightly increased pressure I will have using the DE?
    27' Round Might Sun AG Pool 18000 Gallon Intex Krystal Clear SWG Hayward Pump/Filter on a Timer

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    linen's Avatar
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    Re: Water Pressure

    For your 10500 gallon pool a minimum sand filter size of 2.0 sq. ft. is recommended. Your current filter is 1.76 sq. ft., so it is not too far off. What matrix pump do you have?

    Quote Originally Posted by crokett
    Oh, with the pressure already that high, I got a bag of DE today intending to add some to the filter. Should I be worried about the slightly increased pressure I will have using the DE?
    Should be okay, since you should be only raising the pressure by 1 psi when you first add the DE. Have you read: http://www.troublefreepool.com/pool-..._a_sand_filter
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Water Pressure

    Yes, I have read the pool school link on adding DE.

    My pump, not sure the specific model # but I know the nameplate says 1.5 HP. I also know that motor ratings are sketchy and can mean more or less whatever the manufacturer wants them to mean.
    27' Round Might Sun AG Pool 18000 Gallon Intex Krystal Clear SWG Hayward Pump/Filter on a Timer

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    linen's Avatar
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    Re: Water Pressure

    That 1. 5hp matrix is a bit big for that filter, which has a 35 gpm rating and the pump is probably pushing closer to 55 gpm through it if you have fairly normal plumbing sized at 1.5" diameter.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Water Pressure

    Hmm... is that a problem for the pump and/or the filter? I don't really have the money to replace a filter that is working just fine.
    27' Round Might Sun AG Pool 18000 Gallon Intex Krystal Clear SWG Hayward Pump/Filter on a Timer

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    linen's Avatar
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    Re: Water Pressure

    Sort of both, you filter is too small for your pool (though it's close) and your pump is too big for your filter and could be channeling your sand.

    When you did backwash how long did it take for your water to run clear?
    When your pump is off is your pressure gauge reading 0?

    Bottom line, if you pool is crystal clear, then the filter is doing it's job.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Water Pressure

    The sight glass runs clear in a minute or so, but I've never really timed it. There is a little bit of sand in the sight glass. I haven't ever been able to get that out. I don't get sand in the return though, at least as far as I know. When I turn the pump off the pressure drops to 0. As you said, the filter is working, the pool is perfectly clear. I guess for now I won't borrow trouble. I will keep an eye on things and come fall if there are no issues till then will take the valve assembly off the filter and look at it. Will I be able to see the sand being channeled?
    27' Round Might Sun AG Pool 18000 Gallon Intex Krystal Clear SWG Hayward Pump/Filter on a Timer

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