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Thread: Need help with Cl and CYA levels

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    Join Date
    Feb 2018
    Location
    Raleigh, NC
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    Need help with Cl and CYA levels

    Hello,

    I am a new hot tub owner and I am slowly learning the intricacies of spa chemistry. I have read the stickies which are incredibly helpful, but I could still use some advice. The hot tub is 280gal at 100F. The water is clear and feels fine, but I just tested using the Taylor FAS-DPD kit and it appears that my CYA has become way too high. Here are the current values:
    pH: 7.4
    TA: 70ppm
    CH: 220ppm
    FC: 8.5
    CC: 1.5
    CYA: ~140ppm (mixed with half fresh water, tested at around 70ppm)

    It is entirely possible that there is some user error with the testing procedure, so please keep that in mind. First of all, shouldn't CC be higher than FC? If I drain half the tub to get CYA levels down, how do I bring up Cl without adding CYA? I have a couple different types of chlorine powder, but I assume they both have CYA. Do I run to the store and get some liquid chlorine?

    Thanks!
    Dave

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    AftonJeeper's Avatar
    Join Date
    May 2017
    Location
    Twin Cities, MN
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    1,147

    Re: Need help with Cl and CYA levels

    Yes, You will need to run and pick up some liquid chlorine. In the sticky you should only use dichlor until your CYA is about 30 then switch to liquid.

    CC should be below FC and ideally below 1. Maintain a FC according to this chart: FC/CYA Chart

    Good luck!
    20'x48' 40,000 gal. Vinyl, Pentair Intelliflo 2 VST, Sta-Rite PLM300 System 2 Cartridge Filter, and a Pentair Mastertemp 250 heater all controlled by Pentair Easy Touch with Screen Logic. Dolphin Premier pool attendant.
    I've got iron stained well water. TF-100 and Speed Stir, Lamotte 3017-G for Borates

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    Join Date
    Feb 2018
    Location
    Raleigh, NC
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    Re: Need help with Cl and CYA levels

    Excellent, thank you for the info. I ended up taking a water sample to the local pool/spa store and had them test it. It turns out that the levels were all great (FC around 3.5, CYA around 50). Apparently I just don't understand how to use this new testing kit. Fortunately I had not started draining the tub or anything like that. The shop said they have a simpler testing kit and some great test strips coming in soon, so I may see if I have better luck with them.

    Thanks again,
    Dave

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    Mod Squad mknauss's Avatar
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    May 2014
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    Re: Need help with Cl and CYA levels

    Welcome to the forum!

    If you read through this forum a little, you will notice that we do not recognize Pool Store tests as accurate. You have a quality test kit, it is your water your managing, and you will test it far more accurately than any Pool store.

    Good luck.
    6000 Gallon IG Fiberglass with integrated Spa
    Pentair CCP240 Cartridge Filter with Pentair Intelliflo 3050VS Pump and Pentair HTR250 heater. IC40 SWG. EasyTouch 4. TF 100 Test Kit w/SpeedStir!
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    Marty

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