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Thread: Pretty good start but couple Ph and CYA ?'s

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    maryann79's Avatar
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    Pretty good start but couple Ph and CYA ?'s

    OK, so pool went up Friday, was filled by Saturday afternoon.
    It looks great, and water is nice and clear! (thanks to you all).
    I do have a couple questions, but first, here are my average numbers:

    FC: runs from 3-5 (I usually add liquid chlorine at night to keep it in the 4 or 5 range)
    TC: 3-5
    CC: after first day or so, it's mostly 0, occasionally .5
    Ph: Started high at 8.0, then took it too far down to 7.0. Now it's staying around 7.6-7.7
    TA: First landed at 80, is now consistently 100
    CYA: 50

    1) I'm having to fight to keep the Ph down far enough. Would this be because the TA needs to come down? We have been running the pump 24/7, but 90 percent of the time on low speed. Is it possible the pump is running too much, as in aerating a little much, thus increasing Ph?

    2) CYA--I thought I was careful to not over-add, and the sock method worked great. The reading showed up pretty quickly, within a day or two. I've tested it several times (have run out of CYA reagent, in fact), and it does hold steady at 50. But since the results often don't show up for several days, is it possible/likely that if I test this weekend (the 1-week mark) that a higher CYA will show up? That I really don't want.

    Thanks!
    Pool: 27' x 52" AG, about 16,500K, cartridge filter
    Waterway 175 sq ft 1.5 hp pump 2-speed
    Deck first of June!

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    Smykowski's Avatar
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    Re: Pretty good start but couple Ph and CYA ?'s

    Sounds like you're on your way.

    pH and TA sounds just fine. I wouldn't explicitly try to lower your TA. It's close enough, and when you add acid to lower pH, TA will come down as well. Try to find your pool's sweet spot for pH, and don't be too aggressive. It might settle into stable at 7.7, but if you're too aggressive with chemicals, you might seesaw around it.

    You are correct about CYA. There seem to be instances where it shows up right away. Did you add any other type of chlorine besides liquid bleach? Or was the sock method your only way to add stabilizer.

    My only other (strong) suggestion is to keep your FC a little higher. With a CYA of 50, you want to never go below 4. When you dose the pool, I'd target 7-8, so when it falls, you always stay above that minimum.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
    The most important article on this site - The ABCs of Pool Water Chemistry

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    Re: Pretty good start but couple Ph and CYA ?'s

    Hey,

    I think those numbers look great and your grasp of pool water management is spot on.

    1. I would disregard TA ....except.....rising pH is a fact of life in most pools and muriatic acid is almost as much of a given as chlorine. Dropping your TA will NOT reduce the total amount of acid you put in the pool but will reduce the rate at which pH increases. My practice has been to test TA about every couple of weeks and just go with whatever level my pool decides.

    2, I think your CYA is finished. It often dissolves much quicker than a week but we put that time in there as a cushion because some people have actually reported that it takes a full week. (Mine takes about 3 days, too)

    Enjoy your pool this summer and I would suggest making no further changes. I assume your water looks good?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    maryann79's Avatar
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    Re: Pretty good start but couple Ph and CYA ?'s

    The water does look great.

    I haven't been using MA out of fear of handling it, but I think I need to get over that. Does using Ph minus not work as well, or is it an expense factor?

    It's supposed to rain today, so I'll definitely boost up the chlorine, and then I'll expect a Ph difference.

    Thanks for the help!!
    Pool: 27' x 52" AG, about 16,500K, cartridge filter
    Waterway 175 sq ft 1.5 hp pump 2-speed
    Deck first of June!

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    Re: Pretty good start but couple Ph and CYA ?'s

    Don't be afraid of the MA!
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
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    Re: Pretty good start but couple Ph and CYA ?'s

    I haven't been using MA out of fear of handling it
    Try this....Using someone who's tall enough, reach over the top of the pool and submerse the 1 gallon jug 3/4 of the way into the water......that'll take away a lot of the weight.

    Next, carefully remove the cap and, using a knife or pencil (the acid has little affect on a wooden pencil), remove the seal rinsing everything in the pool water as you remove it.

    Now that the seal is gone (still 3/4 submerged) slowly tip it over and gently pour roughly 1 quart (1/4) of the jug into your pool....you should be standing in front of a return.

    Tip the jug back up, put the cap back on it and you're done!...no spills...no splashes....easy

    That will lower your pH of 7.8 down to around 7.2 or 7.4
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Smykowski's Avatar
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    Re: Pretty good start but couple Ph and CYA ?'s

    Quote Originally Posted by maryann79
    I haven't been using MA out of fear of handling it, but I think I need to get over that. Does using Ph minus not work as well, or is it an expense factor?
    Expense factor. Follow the guidelines duraleigh gave and you'll be fine. Just treat it with respect. I think the issue with MA vs. all the other dangerous chemicals we have in our houses (cleaners, paint thinner, etc.) is that it fumes so easily,
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
    The most important article on this site - The ABCs of Pool Water Chemistry

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    maryann79's Avatar
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    Re: Pretty good start but couple Ph and CYA ?'s

    So we're expecting our first real couple days of rain since the pool went up. Last night at 6:30 pm, the FC was at 2.5, so I put in the recommended amount to take FC to 6. A couple hours later the FC was reading at least 5 (off the chart, as they say). Again this morning, FC reading was at least 5. But in both cases the Ph had gone up from yesterday's 7.6 to 8.0, just in the couple hours between adding the bleach and retesting. No rain has fallen yet. Ph was still the same this morning, maybe had come down a bit to 7.9.
    Would adding the bleach change the Ph?
    Pool: 27' x 52" AG, about 16,500K, cartridge filter
    Waterway 175 sq ft 1.5 hp pump 2-speed
    Deck first of June!

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    Mod Squad Bama Rambler's Avatar
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    Re: Pretty good start but couple Ph and CYA ?'s

    Adding bleach temporary raises pH but the sanitizing action is acidic so the net result is pH neutral. In other words, don't worry about it.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
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