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Thread: Should I raise my CYA ?

  1. Back To Top    #1

    Join Date
    May 2015
    Location
    Mechanicsville, Va
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    12

    Should I raise my CYA ?

    Hello again wonderful people of TFP!

    I have a question regarding my daily chlorine use & CYA level.

    Back on July 8th I raised my CYA from 30 to 45. Prior to July 8th I was adding around 44oz of 12.5% daily on a consistent basis.

    Since raising the CYA to 45,(I say 45 because it's exactly halfway from 40 to 50) I am adding 77oz daily.

    It has definitely been hotter since July 8th around here, but shouldn't I be using less chlorine daily with a higher CYA? This was my only intention when raising the CYA.

    Since I know you like numbers, here they are from my usual evening testing.(Last night)

    CL 2.5
    PH 7.5
    CH 375
    TA 80
    CYA 45 (although I have been using 50 for my CL level)

    I target 6 CL and test an hour after adding, to make sure my pool size, chlorine % and math are correct. I don't like the CL dropping as low as it is which is another reason(more important reason might I add) for thinking I should raise the CYA more.

    Thanks again for all your help, just being here & reading everyone else's threads and your answers has been a tremendous blessing for this first time pool owner! You Rock!!

    P.S. Yes, my water is crystal clear!
    16x32 In-ground 22,000 gallon vinyl liner pool. 1HP Hayward Super Pump. Sand filter.

  2. Back To Top    #2
    Mod Squad kimkats's Avatar
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    Re: Should I raise my CYA ?

    I am not sure but I also want to hear the answer from someone that might know. I love to learn new things.

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

  3. Back To Top    #3
    Texas Splash's Avatar
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    Re: Should I raise my CYA ?

    Typically yes, you would expect to use less chlorine (FC) with a slightly higher CYA - unless something is eating it. Remember, just because your water is clear doesn't rule-out something is wrong. I would suggest posting a CC reading for us, and also consider doing an OLCT to see if you should consider doing a 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
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  4. Back To Top    #4
    Mod Squad pooldv's Avatar
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    Re: Should I raise my CYA ?

    I think that your chlorine usage is higher because the chlorine level is too low and algae is growing in the pool. CYA of 50 requires minimum chlorine of 4. Every time chlorine drops below 4 the pool is no longer being properly sanitized and algae will start growing. It is important to never let chlorine drop below the minimum level for the CYA level in the pool.

    With CYA of 50 and target of 6 you should target keeping FC at 6 at all times. I would target FC of 7-8 because I like to keep it a little higher. If you know there will be a lot of swimming then raise FC to 9 or 10 before and after swimming to cover the extra chlorine demand.

    It is safe to swim when FC is above the minimum and below shock level. We have been swimming in 25ppm FC with CYA of 70 all week because we are slamming and it has been great.

    - - - Updated - - -

    Oh, and to answer the original question. No, I would not increase CYA.
    TFP Moderator
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  5. Back To Top    #5

    Join Date
    May 2015
    Location
    Mechanicsville, Va
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    12

    Re: Should I raise my CYA ?

    Ok, thanks again!

    CC .5

    I will target 8 & keep it above 4 at all times.

    I will also do an OCLT tonight & post the results tomorrow.
    16x32 In-ground 22,000 gallon vinyl liner pool. 1HP Hayward Super Pump. Sand filter.

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