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Thread: optimal cya level?

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    optimal cya level?

    I'm just SLAMming my pool again.

    Upon testing the water the cya was too low to be read using the r0013. I added more cya and it is now at 30ppm.

    First night of testing, I got through about 5ppm of FC, last night 2.5ppm.

    However, during the day it has been dropping unbelievably quickly. I've poured in the equivalent of 12ppm from mid morning to just now 3.30pm. The only difference betweenlast night and today is the sun. The filter has been running continuously.

    So, whilst I can see the benefit of keeping the cya at 30ppm whilst slamming, I'm wondering what the optimum level is for normal operation. I live in Austin, TX and the pool is in full sun all afternoon.

    I had the cya at about 55ppm last summer and even then was getting through about 3ppm a day - which is a bottle of bleach a day and works out to be pretty pricey.

    Should I add borates? I know that will help with pH stabilisation. What about an algaecide?

    I'm also wondering about being a bit lazy and just using some tabs since the cya is low. My only concern with this is CA - this has remained somewhat high despite not having added any pucks or tabs or powder for almost 2 years and I'm told that it's due to the limestone in the area.
    26,390 gallons IG, Centex plaster, Hayward DE 4820 filter, Century Centurion B2859 pool pump motor.
    Booster pump for polaris 280
    Spa
    Built 1997

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    Mod Squad JVTrain's Avatar
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    Re: optimal cya level?

    For your area, 50 to 60 ppm CYA is likely your best bet. That would minimize your FC losses as much as possible if manually dosing with chlorine.

    Borates can help stabilize pH if you're seeing continual pH rise. What is your TA? What are you maintaining it at regularly?

    Algaecides are not necessary and will not reduce FC usage. They are only useful if you are knowingly going to allow your FC to drop below recommended minimum levels for metals treatment or other reasons.

    Test your fill water. Does it have high CH? Lots of water supplies in TX have higher levels of CH so over time due to evaporation and refills, CH can climb steadily. This can likely by managed for quite some time with careful management of lower TA and pH levels to prevent scaling.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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    Re: optimal cya level?

    ph does tend to rise and I need to adjust it weekly.

    TA is 100-110.

    CH in the fill water was actually pretty low when I tested it - water out of the garden faucet was about 100ppm if I recall correctly. However pool CA is about 425 and has barely gone down in 2 years.
    26,390 gallons IG, Centex plaster, Hayward DE 4820 filter, Century Centurion B2859 pool pump motor.
    Booster pump for polaris 280
    Spa
    Built 1997

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    Mod Squad pooldv's Avatar
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    Re: optimal cya level?

    Lower your TA to 70 or so and that will slow your pH rise. Here's how, Pool School - Lower Total Alkalinity
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    Re: optimal cya level?

    Last year I asked about the TA and since I was ok on the CSI, it was deemed not necessary to adjust.

    Borates will help buffer pH then, and what about the FC usage?

    Going back to my original thoughts..... I could use some pucks which will raise cya and add FC to the pool. Although this will also raise CH as well. If I use the pucks, should I lower the TA first? I know sacrilege to mention pucks on here but hey, I'm a busy mom and that will kill 2 birds with one stone.
    26,390 gallons IG, Centex plaster, Hayward DE 4820 filter, Century Centurion B2859 pool pump motor.
    Booster pump for polaris 280
    Spa
    Built 1997

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    Mod Squad tim5055's Avatar
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    Re: optimal cya level?

    Quote Originally Posted by surfbabe View Post
    Last year I asked about the TA and since I was ok on the CSI, it was deemed not necessary to adjust.

    Borates will help buffer pH then, and what about the FC usage?

    Going back to my original thoughts..... I could use some pucks which will raise cya and add FC to the pool. Although this will also raise CH as well. If I use the pucks, should I lower the TA first? I know sacrilege to mention pucks on here but hey, I'm a busy mom and that will kill 2 birds with one stone.
    Pucks will not raise CH, but they do raise FC, CYA and as they are acidic will help slow the pH rise while you are using them.

    We ar enot against their use, I have a bucket in my stash of supplies. We jsut want folks to know what they are putting in their pool Knowledge is power.
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    Re: optimal cya level?

    Quote Originally Posted by tim5055 View Post
    Pucks will not raise CH, but they do raise FC, CYA and as they are acidic will help slow the pH rise while you are using them.

    We ar enot against their use, I have a bucket in my stash of supplies. We jsut want folks to know what they are putting in their pool Knowledge is power.


    I am so pleased to hear that!

    Let's hope that tonight is the last night of the slam...... fingers crossed.
    26,390 gallons IG, Centex plaster, Hayward DE 4820 filter, Century Centurion B2859 pool pump motor.
    Booster pump for polaris 280
    Spa
    Built 1997

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