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Thread: Numbers-help!

  1. Back To Top    #1

    Join Date
    Jun 2015
    Location
    O'Fallon, MO
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    45

    Numbers-help!

    Numbers today:

    FC 7 after taking to 12 last night. It started raining at 7 right after I poured the bleach in so I didn't do an ONDT. I tested around 11:30 AM & it's sunny out. Not sure how much should drop via sunlight, but just wanted to list the stats.

    TA was either 160 or 190. 160 was more purple. 190 was the same shade of red as when I started.

    CYA I couldn't really read. I filled bottle all the way up which would be 15(?) & could still barely see the dot. I did this in the sunlight. I did it yesterday & got a reading of 20 with not seeing the dot in the house. Today I did accidentally fill the bottle just slightly over with regeant so maybe that would make the difference between 20 & lower or doing in sunlight vs the house?!?

    Alright, wonderful experts, what should I do? Pool is crystal clear & CC is 0. I ordered the over the top skimmer to catch debris better after reading some good reviews so that will help keep stuff off bottom since there are several trees around pool dropping leaves. I've been taking ladder out daily & scrubbing it down plus scrubbing sides daily when we can get in. We seem to have turned into the rain forest here, LOL!

    Thanks in advance everyone!
    24 x 52 intex AG round with well water-water has no issues with rust or other contaminants
    2800 GPH Intex sand filter pump
    Located in Missouri

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    Texas Splash's Avatar
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    Jun 2014
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    South-Central Texas, Marion/San Antonio
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    Re: Numbers-help!

    Well let's see. Here are my observations that I hope you will you:
    - Based on your signature pool size, your pool volume should be about 14,600 gallons.
    - How much FC (by numbers) you lose each day depends on things like exposure to sun, amount of swimming, your CYA, etc. But ideally we like to keep dally FC loss around 2-3 ppm, maybe 4 or so.
    - It sounds as though your TA might be quite high. Normally, TA should go from green after adding the 5 drops, then finally Barbie pink/red. Color change is most important though, so I suspect it is indeed too high.
    - CYA at 15(?). I'm assuming you mean way over 100 right? But then you mentioned perhaps not having the correct amount of reagent? Well, so much hinges on the proper CYA (+/- 10ppm) you really want to have this one closer. Yes, test/read it outside with the sun to your back. After your mix the pool water and reagent, hold the tube at waist level and pour/squirt the mixture into the tube and watch the black dot. After you test it the first time, you can pour everything from the tube back into the mixture bottle, shake, and try it again wit the same stuff. Do this 2,3 4 times or more if you need to so that you are sure you have a constant reading. Only after you are sure the CYA test is accurate can you move forward.

    If the CYA is over 100, you will need to do a partial drain to try and get it at least below 80 ppm. If your CYA is not high and below 80 or so, then simply make sure your FC is at the correct level based on your CYA by looking at the Pool School - Chlorine / CYA Chart. FC and CYA must be matched together like on this chart.

    After you have confirmed/adjusted CYA, the only way to know for sure if you are losing too much FC during the day is to do an overnight test: Pool School - Perform the Overnight FC Loss Test (OCLT). If you have any questions about the info on that page, let us know and we can help further.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  3. Back To Top    #3

    Join Date
    Jun 2015
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    O'Fallon, MO
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    45

    Re: Numbers-help!

    I thought TA was high as well so what do I do about that? Worry about CYA first? My CYA reading is NOT over 100, it is only 15 per the tube or even lower b/c I could still see the dot very faintly. I will repeat the test, though.

    My pool is not quite as full as it should be due to it not being as level as it should be. When I add chlorine based on pool math, it brings it up to ideal level. I've been slamming for almost two weeks. But I'm not sure if I need to keep slamming as I've had one .05 overnight loss & one 1.0. I'm concerned about the CYA being so low but am half scared to add more since being high seems to be such an issue! Will be taking it down in the fall & installing a base for it so I can then leave it up during winter but with all of our rain this year, we just went on & put it up or it was not going to be worth it!
    24 x 52 intex AG round with well water-water has no issues with rust or other contaminants
    2800 GPH Intex sand filter pump
    Located in Missouri

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    Texas Splash's Avatar
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    Jun 2014
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    South-Central Texas, Marion/San Antonio
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    12,981

    Re: Numbers-help!

    To follow-up on your concerns ..... There are two reasons to lower your total alkalinity (TA) right away, because you want to slow down the rate that the PH rises (they work together), or if high TA is contributing to a high calcium saturation index (CSI) which puts you at risk of calcium scaling. You shouldn't lower TA just to reach a target number. Make sure you actually have one of the above issues before lowering your TA.

    The acid/aeration process to lower TA:
    1. Add acid to lower your PH to between 7.0 and 7.2 (this also lowers TA)
    2. Aerate until PH rises to around 7.6 (the only way to raise PH without also raising TA)
    3. Repeat steps 1 and 2 until you reach the desired TA.

    As for CYA, you can (and should) raise that right away to a target of 30. 30 is on the low end, won't hurt anything at all, and will protect your FC (good chlorine) from the sun. Just use the Poolmath calculator and you'll be fine. Remember it takes about a week after the stabilizer is dissolved to show-up on readings. I suspect that because your CYA has been so low that you have not been able to keep the FC consistently and at the appropriate levels required all day long before the sun grabs it. The CYA will help. So yes, if you are still seeing a CC over .5, you need to continue the SLAM.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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