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Thread: My pool is open, it's green, and the numbers are meh.

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    My pool is open, it's green, and the numbers are meh.

    ~35k gallons

    TF-100:

    pH 8.2+ (could this be number invalid due to the high chlorine count? it was just the most purple I've ever seen it)
    FC 25-28/CC 0 (PB dumped chlorine in it and I was surprised the CC is ZERO but it sill surely go up as the chlorine kills the algae)
    CH 225
    TA 40
    CYA <20 (literally I had to fill the bottle to not see the black dot - I did it TWICE to verify, doesn't shock me because last year I kept it around 30-35ish)

    The pool is a green swamp (though the chlorine in there is already doing wonders).

    So I am assuming I should try to both raise my CYA slowly (at least get to 30) in order to stabilize the chlorine as I go through the SLAM process to as well as add some acid to lower my pH to 7.2-7.5ish and perhaps raise my TA by 10-20 points to avoid pH sway.

    Does that make sense?

    Also, how do I use the PoolMath page when my CYA is SO LOW?
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

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    Mod Squad JVTrain's Avatar
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    Re: My pool is open, it's green, and the numbers are meh.

    You're on the money. I'd let the FC come down to 10 naturally, test pH then hit the SLAM. Worry about the TA after you're done getting it clear. Just don't over do it with the lowering of the pH as you don't have much TA. Be sure to use all your numbers into Pool Math when calculating how much MA to add.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: My pool is open, it's green, and the numbers are meh.

    But how do I even figure out how much MA for the PoolMath. I didn't get an exact reading (it's <20).

    I was going to do a baseline of 0 and target of 10 and then retest? Just to be ultra cautious.
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

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    Mod Squad JVTrain's Avatar
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    Re: My pool is open, it's green, and the numbers are meh.

    Your muriatic addition is not affected by your CYA level. Just make sure your TA level (40) is input into pool math as that will have an effect on how much muriatic acid you add to get the desired pH change to 7.2.

    For adding CYA, assume your level is less than 20, perhaps 10. Use pool math again to calculate how much you need to get from 10 to 30 and add that (in a sock) once you start SLAMing.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: My pool is open, it's green, and the numbers are meh.

    Quote Originally Posted by JVTrain View Post
    Your muriatic addition is not affected by your CYA level. Just make sure your TA level (40) is input into pool math as that will have an effect on how much muriatic acid you add to get the desired pH change to 7.2.

    For adding CYA, assume your level is less than 20, perhaps 10. Use pool math again to calculate how much you need to get from 10 to 30 and add that (in a sock) once you start SLAMing.
    I apologize, I don't mean MA, I mean CYA. MA I know. I'll let the chlorine levels get down to 10-13 before adding anything there.

    But you recommend letting the chlorine settle even for adding some CYA? I guess without stabilizer that will take a day maybe two?
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

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    Mod Squad JVTrain's Avatar
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    Re: My pool is open, it's green, and the numbers are meh.

    Because you're holding FC and showing low/no CCs, go ahead and add CYA whenever you want. It will lower pH by a little bit as well, but not much.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: My pool is open, it's green, and the numbers are meh.

    Thanks Joel, that's what I figured which is why I asked. I think I'm going to go with your advice assume my CYA is 10 and try to bring it up to 20 and see what happens. That should at least give me a reading the next time around to add the rest when I start the SLAM.
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

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    Re: My pool is open, it's green, and the numbers are meh.

    Why would you wait to test and lower Ph. It seems waiting to get FC down to 10 will allow the algae to get going again. Why not slam, let FC fall, then adjust PH? Might allow for quicker pool use.


    16 x 32 Sport Pool; Hayward Series Sand Filter S244T
    15,000 Gallons, In Ground with New Vinyl Liner
    Pool approx. Five Years Old. Live in KY

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    Mod Squad JVTrain's Avatar
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    Re: My pool is open, it's green, and the numbers are meh.

    Because with low CYA, you don't lose much ground, if any by letting FC drop to 10 or less. If the CYA were 60 and you needed to be at 24 ppm FC for a SLAM, that's a different situation.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: My pool is open, it's green, and the numbers are meh.

    I see. Just wondering in case I get in that situation.


    16 x 32 Sport Pool; Hayward Series Sand Filter S244T
    15,000 Gallons, In Ground with New Vinyl Liner
    Pool approx. Five Years Old. Live in KY

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