Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 4 of 4

Thread: BleachCalc numbers don't match my chlorine increase???

  1. Back To Top    #1

    Join Date
    Apr 2011
    Brookeland, Texas

    BleachCalc numbers don't match my chlorine increase???

    Ok, last night we started using bleach instead of the cal hypo to chlorinate. My FC level prior to adding bleach was 3.0, I added 2.5gal of 6% clorox to pool last night after dark. This morning the FC is 8ppm. According to BleachCalc it should be at 6ppm for my size pool. I realize that the 52000 gal is just a estimate based on average depth for the pool, but to have increased 5ppm to 8. it says my pool volume would have to be 30000 gallons. The pool is 24' x 48', 4' to 8' deep has a set of stairs in one corner of the shallow end and a swim out ledge in both corners of the deep end. this may account for 1 ot 2 thousand gallons at most. Am I missing something here??

    My Current numbers are:

    PH - 7.5
    FC - 8
    CC - 0
    CYA - 60
    TA - 90
    CH - 200
    12k gal. Free form 14' x 28' IG gunite, 8' raised spa, Hayward T15 SWG, Hayward Ecostar VS pump, Hayward Super II pump, Booster pump, Polaris 280, Hayward DE 7220 filter, 400k Btu heater, Color logic LED lights. Pro Logic controller with remote.

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: BleachCalc numbers don't match my chlorine increase???

    It is very likely that your pool is noticeably smaller than 52,000 gallons, though it seems unlikely that it could be as small as 30,000 gallons. I would guess at something closer to 40,000. There are a couple of ways to approach this. The simplest is to take this as a hint that the pool is smaller than you thought, and to continue watching other chemical additions to see what they do, adjusting your size estimate down over time if all/most of your chemical additions behave similarly.

    Another approach is to do some additional measuring. How long is the shallow end, how long is the slope between shallow and deep, how long is the deep end. Are the corners fairly square, or are they rounded? Do the walls go straight down, or are they sloped anywhere? And so on.
    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

  3. Back To Top    #3

    Join Date
    Apr 2008
    Central Texas

    Re: BleachCalc numbers don't match my chlorine increase???

    When we bought our place, the previous owners (who had the pool built!) told us it was a 35,000 gallon pool. But my chemical additions always seemed to fall far short of the expected result. Then one spring I drained and cleaned the pool and then measured the water it took to fill it back up. It came in at 24,000 gallons, not 35,000.
    26,000 Gallon Gunnite IGP
    2 HP Challenger High Head Pump
    60sf Nautilus DE filter
    Polaris 280

  4. Back To Top    #4

    Join Date
    Mar 2010
    Spring, TX

    Re: BleachCalc numbers don't match my chlorine increase???

    I have the same issue as well. I use the calculator and the few times I have tested right after addition of bleach, it goes higher than expected. So I just let it go and maybe the next day I am good to go without having to worry about doing much.
    13,000 Plaster IG Pool approx
    Hayward C5030 Cart Filter
    Emerson 1081 EB653 1.0 HP 1.40 S.F. 3450 RPM
    Pool Calculator, Pool School, TF Test Kits

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts