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Thread: Rate of Evaporation?

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    Rate of Evaporation?

    Is it normal to lose about an inch of water through evaporation over the course of a week, or a week and a half? It hasn't rained in 19 days and the solar blanket hasn't been on in well over a month. Some days have been quite hot, and some about have been comfortable. I have added water about 3 times in the last month. Thanks.
    16 X 32 Vinyl. Hayward aqua rite salt system, T -15 cell. Hayward H250 gas heater, Hayward 1HP superpump.

  2. Back To Top    #2

    Re: Rate of Evaporation?

    Pretty normal here in SoCal, probably a little light for Phoenix! Really depends on where you live.

    Try a bucket test if you think you have a leak. That should tell if you are experiencing normal evaporation or have a problem.


  3. Back To Top    #3

    Join Date
    Mar 2007
    San Rafael, CA USA

    Re: Rate of Evaporation?

    A map of annual water evaporation rates is here. In areas with a cold winter, most of the evaporation is during the summer so 50" per year is really more like over 6 months so that's nearly 2" per week. So you are doing really well with only 1" per week loss. As Bruce noted, a bucket test can tell you if you have a leak. Note that in Leak Detection you should put the bucket onto stairs in the pool so that the water in the bucket is at the same temperature as the pool. Evaporation rates are very dependent on temperature (and on wind).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  4. Back To Top    #4

    Join Date
    Jul 2009
    Eden Prairie, MN

    Re: Rate of Evaporation?

    Wind speed at the water surface also affects the evaporation rate.
    AGP partially buried, with surrounding deck and flower bed. 12 x 24 oval x 48" deep Celebration by Forum. Steel sides, vinyl liner. Hayward 2 HP sand pump. Flower fountain - works well to cool water up to 10 degrees.

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