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Thread: Missing CYA

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    Join Date
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    Missing CYA

    I just tested my water today (Taylor 2006 kit), and my CYA reading is baffling me. I couldn't get any reading. It was basically clear when the vial was full. Now last summer I had added a bunch of CYA and it tested around 50 or so. I double checked with the pool store, and they also didn't see any CYA. So my question is, where did the CYA go? It's my understanding that the only way to get rid of it was to replace water.

    We had a wet winter here in Northern California, but it wasn't due to rain dilution as I have a safety cover and use a cover pump to remove the rain off it. The pool store suggested I might have a leak, but I'm pretty sure I would have noticed that in my water bill. Besides, my salt level hasn't gone down much (3300 to 3200). If my water was heavily diluted then I'd expect low salt levels as well. Anyone have any ideas?

    Alex
    30,000 gallon outdoor 18'x40' plaster pool, replastered in 2009. Pentair VS pump, Jandy CL-340 cartridge filter, Pentair IC-40 salt system, Pentair SunTouch control system, Pentair Legend pressure side pool cleaner, 10 Fafco panel solar panels, automatic pool cover.

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    Mod Squad Texas Splash's Avatar
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    Re: Missing CYA

    Hi Alex and welcome to TFP. While CYA is typically lowered by water exchange, a small amount (3-5 ppm) is oxidized each month from use, not to mention splashout. If it's been about 10 months or so, that could be 40 to 50, not to mention the +/-15 degree of testing variance. Regardless, if you're low, now's the time to add.
    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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    Richard320's Avatar
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    Re: Missing CYA

    Under certain conditions CYA can break down into ammonia.

    Search Ammonia here and you'll find a whole bunch of threads.

    What are your test results? Low FC and high CC are a pretty good clue if that's where the CYA went.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    AimeeH's Avatar
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    Re: Missing CYA

    Welcome to TFP

    I hope someone else can chime in but I'm pretty sure (last year in particular) we have seen several cases of CYA disappearing over a winter often causing an ammonia problem. You will see a HUGE chlorine demand if that is the case.




    And Richard and Texas beat me to it
    18*36*23 true "L" vinyl IG 29,000 gallons. SWG. TF-100 test kit.
    http://tftestkits.net/splash-page.html

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    Re: Missing CYA

    Ok, ammonia might be what's going on here. My salt cell croaked recently, so I was running with zero chlorine for some time (not sure when it died). I just installed the new cell Sunday and added some bleach to help to get going. Testing this morning, FC was only 1. I lazily didn't test CC at the time. I of course added some CYA and some more chlorine before reading these replies. Right now, testing after adding some bleach FC is 4 and CC is .5.

    I'll see what it is tomorrow morning. If I understand things, I just fed the critters some fresh CYA, so I should expect little to no FC and a high CC, correct?
    30,000 gallon outdoor 18'x40' plaster pool, replastered in 2009. Pentair VS pump, Jandy CL-340 cartridge filter, Pentair IC-40 salt system, Pentair SunTouch control system, Pentair Legend pressure side pool cleaner, 10 Fafco panel solar panels, automatic pool cover.

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    Richard320's Avatar
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    Re: Missing CYA

    Quote Originally Posted by AlexR View Post
    Ok, ammonia might be what's going on here. My salt cell croaked recently, so I was running with zero chlorine for some time (not sure when it died). I just installed the new cell Sunday and added some bleach to help to get going. Testing this morning, FC was only 1. I lazily didn't test CC at the time. I of course added some CYA and some more chlorine before reading these replies. Right now, testing after adding some bleach FC is 4 and CC is .5.

    I'll see what it is tomorrow morning. If I understand things, I just fed the critters some fresh CYA, so I should expect little to no FC and a high CC, correct?
    Not necessarily. The bleach you added packed a pretty good punch since it wasn't buffered at all with CYA. You might have killed whatever bacteria it is that ate the original CYA.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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