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Thread: Water Readings (after adding bleach this am)

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    Water Readings (after adding bleach this am)

    Initial reading this morning
    FC....0
    PH 7.2-7.3

    so we added 96oz of bleach at 9am and another 48oz at 10:00ish. Just did another test and the results are as follows

    FC....1
    CC....0
    TC....1
    PH....7.5
    TA....110 (this has increased from 100 the two previous days)

    How long does the bleach take to circulate b/f getting a good FC reading....did we take the test too soon after adding the bleach?
    Or should I go and add more bleach. The sun is out and hits our pool starting at 8am each day.

    Concerned about the TA and PH increasing too much.

    Can someone assist with the next step please?

    Thx.
    18x36 IG Vinyl Grecian Lazy L (20k gallons) ~ Whisperflo DS 2.0HP pump ~ QuadDE100 filter ~ Autopilot SWG DIG-60 ~ (7) 4x16 solar panels

  2. Back To Top    #2
    JasonLion's Avatar
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    You can test the FC level 30 minutes to an hour after adding bleach. So you did the test correctly.

    You added enough bleach to raise FC by about 3 1/2 and then it fell to 1 in about two hours. You must either have a very low CYA level, which can cause rapid loss of chlorine to sunlight, or there is something in the pool that is consuming chlorine (perhaps the start of an algae bloom).

    The next thing to do is to get your CYA level tested and adjust it to between 30 and 50. If CYA is already 30 or higher you need to shock the pool.
    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
    The rule of thumb is that 6% bleach raises 10,000 gallons 6ppm. Since your pool is 20,000, and you added .75 gallons, you should, IN THEORY, get to about 2.25 ppm if I did my math right. That chlorine might have spread through the pool already but been used up by organic materials. I would generally expect a liquid addition like bleach to have dispersed throughout the pool in a half hour, but it depends on your pump and how fast your pool circulates water. You may have also lost some to sun.

    You can safely add another thing of bleach of the same size and concentration. It won't make the pool too high to swim.

    In the end, only testing will really give you a good picture of how much chlorine you have. If you want, you can wait 20 minutes, test again, and if you've seen no change at all, then it's probably done circulating.

    What test kit are you using? Is it possible the results are not accurate?

    The pH will increase some but not that much from bleach. Still, it's good to test it. Don't worry about increasing the TA from the bleach. If you need chlorine, you need to add bleach. When that is straightened out, then worry about the TA.

  4. Back To Top    #4
    JasonLion - I have not added any CYA to our pool yet b/c I thought we needed to get the FC levels first. we had the leak in our pool Friday into yesterday afternoon.

    1) Do you suggest I go add the stabilizer now? (which I have the liquid so it should take affect more rapidly)
    2) How soon after adding the stabilizer should I add more bleach?
    3) how soon after the two above steps can the kids go swimming? (they have been bugging me all morning, typical of the excitement of a new pool, I know)

    Thx.
    18x36 IG Vinyl Grecian Lazy L (20k gallons) ~ Whisperflo DS 2.0HP pump ~ QuadDE100 filter ~ Autopilot SWG DIG-60 ~ (7) 4x16 solar panels

  5. Back To Top    #5
    JasonLion's Avatar
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    Without any stabilizer the chlorine would be lost to sunlight quite quickly, so no reason to suspect algae.

    Yes, add stabilizer now. If you have the liquid form it will mix in about half an hour with the pump running. Then bring the FC level back up with bleach and you should be good to go.

    You can swim half an hour after adding CYA or bleach. The pool should actually be safe right now even without the chemicals because the chlorine you added earlier would have been very effective with CYA near zero. It is only that you don't want to be swimming while adding chemicals because the local concentration in some spots can be very high until it has mixed in.
    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

  6. Back To Top    #6
    We just added 2gal of the liquid stabilizer which says it should bring the CYA to approx. 32ppm. Should we add more right now or is this sufficient to at least hold the chlorine? I know our CYA should be bwtn 40-80, maybe higher once the SWG starts up this week.

    So, more stabilizer or add the Cl in a 1/2 hour?
    18x36 IG Vinyl Grecian Lazy L (20k gallons) ~ Whisperflo DS 2.0HP pump ~ QuadDE100 filter ~ Autopilot SWG DIG-60 ~ (7) 4x16 solar panels

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    JasonLion's Avatar
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    CYA at 30 is plenty for today. With a SWG you will want CYA between 60 and 80. Test CYA again tomorrow and see where it is and adjust it from there at that time.
    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

  8. Back To Top    #8
    CYA...30
    PH....7.5
    Cl.... .5

    and I just added 1.5 more gallons of bleach.

    I will test again in the morning.

    When would you suggest I start adding my pool salt? When my FC levels are "stable"?

    Thx for all of your help today!
    18x36 IG Vinyl Grecian Lazy L (20k gallons) ~ Whisperflo DS 2.0HP pump ~ QuadDE100 filter ~ Autopilot SWG DIG-60 ~ (7) 4x16 solar panels

  9. Back To Top    #9
    Be careful when adding CYA. You can't get rid of it except through dilution (i.e. partially draining and refilling the pool). Always err on the side of caution... add less than you think you need, WAIT, test again, and if you still need more, add, again, less than you think you need.

  10. Back To Top    #10
    JasonLion's Avatar
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    You can go ahead and add salt any time.
    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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