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Thread: Is my CYA too low?

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    Join Date
    Mar 2015
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    Richardson
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    Is my CYA too low?

    We live in Dallas TX, we had record rainfall last month, one two day period was over 12", raining almost faster than the overflow could drain. Earlier in the spring I drained the pool to reduce the CYA from 80+ to 40, but now it is around 30.

    There is a lot of shade around the pool, but it probably still gets a good 6 hours of sun on it a day. This week has been sunny and hot (93+), a more typical summer day, and I am still determining how much chlorine I am losing a day - it is starting to look like it is 2-3 ppm. Water temperature is around 86, pool is about 27,000 gallons. There are only two of us using the pool mostly on the weekends and a few hours during the week.

    I've read the lower the CYA the more chlorine I will be using, are there any other negatives for a low CYA?

    We have a new 50 lb bucket of 3" trichlor pucks we bought last year, before we knew what were doing. Can I use those to raise the CYA, if needed? We were going on vacation at the end of July, so I was planning on leaving 10-12 pucks floating around the pool in the dispensers for the week, but maybe that should be a future topic.

    thank you
    27,000 gallon, dark gray Sunstone quartz aggregate plaster, Hayward DE filter, Dallas TX

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    Mod Squad tim5055's Avatar
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    May 2014
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    Re: Is my CYA too low?

    I would say it is too low, but if it is fact shaded most of the day then you may be OK. I would test your water morning & night for a few days to see what you are loosing to the sun and go from there.

    Yes, you can use the pucks to slowly raise your CYA. I'm doing that right now, I have 5 pucks floating to bring my CYA back from 40 to 50. In your pool each puck should be about 2ppm raise.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: Is my CYA too low?

    Quote Originally Posted by tim5055 View Post
    I would say it is too low, but if it is fact shaded most of the day then you may be OK. I would test your water morning & night for a few days to see what you are loosing to the sun and go from there.

    Yes, you can use the pucks to slowly raise your CYA. I'm doing that right now, I have 5 pucks floating to bring my CYA back from 40 to 50. In your pool each puck should be about 2ppm raise.
    Just watch your pH when adding pucks as it will likely drop. My pool has a gradual pH rise of about .1 every 2-3 days, but with a few pucks in an inline feeder I was getting a pH drop of .1 over 2 days.

    Mike
    Built 1980, 19' x 30' almost rectangular, screened 15,000 gal, plaster, Hayward DE 3620 filter (currently using cellulose), Emerson 1081 1HP pump, AquaCal Heatwave SuperQuiet SQ110R heater, Zodiac T5 Cleaner, Taylor K-2006 test kit

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    Mod Squad tim5055's Avatar
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    Re: Is my CYA too low?

    Quote Originally Posted by mikech View Post
    Just watch your pH when adding pucks as it will likely drop. My pool has a gradual pH rise of about .1 every 2-3 days, but with a few pucks in an inline feeder I was getting a pH drop of .1 over 2 days.

    Mike
    Very true. I have not had to add any acid to bring down the pH once the floaters went in.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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