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Thread: Need some help please

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    Need some help please

    Hi all,
    I have an AGP and noone has swam in it since Sept 3rd but the water level has gone down about 3-4 inches. It's a brand new pool, Do you think I have a leak or is this pretty normal? Thanks in advance for any help/comments on this.
    27 ft. round AG pool with 54" walls, 18,065 gallons, 22inch Sparco sand filter with 2.0 HP 2 speed pump

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    JasonLion's Avatar
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    Here is a good place to go to calculate what normal evaporation for your area should be.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    duraleigh's Avatar
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    HI, PDS,

    Welcome to the forum. Water levels in the South typically drop 1/4 inch (give or take) per day from evaporation and whatnot. If you haven't added since Sept 3rd (17 days), that's about 3-4" so I would suspect it's normal. No guarantee that you don't have a leak, but that seems pretty typical of pools here in the South.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Given our lack of rain, and this fun heat wave we are having, I would suspect it is just evaporation.

    8000 gallon 20' x 48" round vinyl frame pool, 12" sand filter (don't have the specs on the pump), TF100 test kit
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    donaldm823's Avatar
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    Evaporation Loss at Night

    I have seen the majority of my evaporation occur at night if the night is cool and the pool water warm. Here in PA it typically goes down to 60F at night with my pool water at 85F-you can see the steaming off of the water surface-which is water loss. I control it now by installing my solar cover at night-it minimizes both the heat loss and the fluid loss. Not sure if you are in the Kentucky mountains, if so you may be seeing the same thing as I.
    Don SW Florida
    10,000 gal in ground concrete pool
    Pentair Cartridge filter, Pentair SWG, Pentair Intelliflow VS pump (11018)
    FAFCO solar panels w/Pentair SolarTouch controller
    using BBB for pool chemistry/Lamotte ColorQ tester for daily testing

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    Evaporative loss is normally greatest when the temperature/dewpoint spread is the widest.....mid-afternoon on a normal, clear day. Wind (mixing of the atmosphere) is a significant contributor.

    The "steam" you see (usually at night and early AM) is actually condensation. The air temp just slightly above the pool water warms a little and is able to accept more water vapor (gaseous). As that tiny layer of warmer air rises, it is quickly cooled by the surrounding atmosphere and becomes totally saturated....producing condensation (wherein the water vapor returns to it's liquid state).

    You do not see the "steam" (condensation) in the daytime because the surrounding atmosphere has a wider temp/dewpoint spread and can accept far more water in it's gaseous state. The greater the temp/dewpoint spread, the more evaporative loss occurs. Those of you living in the desert Soutwest in that low relative humidity can attest to that.
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    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    donaldm823's Avatar
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    Quote Originally Posted by duraleigh
    Evaporative loss is normally greatest when the temperature/dewpoint spread is the widest.....mid-afternoon on a normal, clear day. Wind (mixing of the atmosphere) is a significant contributor.

    The "steam" you see (usually at night and early AM) is actually condensation. The air temp just slightly above the pool water warms a little and is able to accept more water vapor (gaseous). As that tiny layer of warmer air rises, it is quickly cooled by the surrounding atmosphere and becomes totally saturated....producing condensation (wherein the water vapor returns to it's liquid state).

    You do not see the "steam" (condensation) in the daytime because the surrounding atmosphere has a wider temp/dewpoint spread and can accept far more water in it's gaseous state. The greater the temp/dewpoint spread, the more evaporative loss occurs. Those of you living in the desert Soutwest in that low relative humidity can attest to that.
    Your explanation sounds real "official/technical" to me, but condensation means my pool level should rise-which in fact it does not-just the opposite. But my solar cover comes off every day at 1200 and back on at 1800. The only time my water level goes down is when I do not install my solar cover at night. I also run my pool pump ONLY during the day. With these facts in mind, how do we explain the NO decrease in water loss (almost 0) when my solar cover is on at night??? Just the other day, I was too lazy to install my solar cover, and it dipped down to 54F (my pump was off), and wa, la, I lost almost a half inch in water level. There was no loss in water level during that same day (it got up to 80F)(the pool was at 88F since I have a heater).
    Don SW Florida
    10,000 gal in ground concrete pool
    Pentair Cartridge filter, Pentair SWG, Pentair Intelliflow VS pump (11018)
    FAFCO solar panels w/Pentair SolarTouch controller
    using BBB for pool chemistry/Lamotte ColorQ tester for daily testing

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    MikeInTN's Avatar
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    Quote Originally Posted by donaldm823
    Quote Originally Posted by duraleigh
    Evaporative loss is normally greatest when the temperature/dewpoint spread is the widest.....mid-afternoon on a normal, clear day. Wind (mixing of the atmosphere) is a significant contributor.

    The "steam" you see (usually at night and early AM) is actually condensation. The air temp just slightly above the pool water warms a little and is able to accept more water vapor (gaseous). As that tiny layer of warmer air rises, it is quickly cooled by the surrounding atmosphere and becomes totally saturated....producing condensation (wherein the water vapor returns to it's liquid state).

    You do not see the "steam" (condensation) in the daytime because the surrounding atmosphere has a wider temp/dewpoint spread and can accept far more water in it's gaseous state. The greater the temp/dewpoint spread, the more evaporative loss occurs. Those of you living in the desert Soutwest in that low relative humidity can attest to that.
    Your explanation sounds real "official/technical" to me, but condensation means my pool level should rise-which in fact it does not-just the opposite. But my solar cover comes off every day at 1200 and back on at 1800. The only time my water level goes down is when I do not install my solar cover at night. I also run my pool pump ONLY during the day. With these facts in mind, how do we explain the NO decrease in water loss (almost 0) when my solar cover is on at night??? Just the other day, I was too lazy to install my solar cover, and it dipped down to 54F (my pump was off), and wa, la, I lost almost a half inch in water level. There was no loss in water level during that same day (it got up to 80F)(the pool was at 88F since I have a heater).
    The condensation is still airborne, so your pool won't rise at all. It's no different than fog, basically. For your pool to steam off water vapor, your water would have to be around 212 degrees F, or you'd have to live in a vacuum.

    I would guess the reason you don't see much evaporation during the daylight hours is that you have the pool uncovered for 6 hours, and covered back up for 18. To prove/disprove, get really, really lazy and leave it off from 0600 - 1800 or till sundown, and see how much you lose.
    24' x 52" AGP - approx 13,500 gallons
    Pentair Optiflo 1 hp/2sp pump w/ Swimpro Voyager 150 sq ft cartridge filter
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