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Thread: CYA Added, But Testing Week Later Shows Little Rise

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    CYA Added, But Testing Week Later Shows Little Rise

    So I opened my pool a few weeks ago. Weather has been awful and no one has even swam in the pool yet (my ladder isn't even installed yet). Weather has only been in the 60's to 70's with a lot of rain and overcast days. Tested my CYA and it was below the readable level in the tube (I have the CYA test from TF Test Kits I bought last season as my reagent ran out last year). So I assumed a level of 10 and added 100% Cyanuric Acid (Omni branded Chlorine Stabilizer granules that I purchased new in April 2011) to bring it up to a target level of 35 (used pool calculator). I added the granules to 2 panty hose and hung them in front of my return jet. Ran the pump continuous for 24 hours and then set it back to timer mode (2 hours on, 4hours off for a total of 8 hours of "on time" per day). The CYA was out of the panty hose after a few hours. I did not backwash the filter until one week later (prior to CYA test #2).

    One week later (last Saturday) I test the CYA again and again it's below the readable level! At the top of the tube the mixture was starting to look cloudy as if the dot would disappear with a little more solution, so I assumed a level of 15 and raised it to a level of 34 (that was all the CYA I had left in the bottle).

    My questions: 1) Shouldn't I have read at least 25 at my second test even if I was 0 during the first test? 2) Is Cyanuric Acid (granular) something that loses strength and should be bought fresh each year? Could it be that mine has lost it's potency? It has always been stores in the original bottle out of the sun inside a shed (and in my basement this past winter).

    I do feel confident in my testing procedure as far as mixing appropriate amounts of pool water and reagent go and mixing properly (shaking vigorously, waiting min. 30 secs, shaking vigorously again). My chlorine depletion has been much faster than I have expected (especially with the nasty weather we've been having) so that seems to indicate that my CYA is much lower than it should be. I've been seeing it drop 5 to 6ppm per day! I did suspect that perhaps my liquid chlorine had lost some potency, but testing a few hours after adding shows a reading near what I expect. One thing I don't like is that I can't test CYA again for another week! And I'm learning that I can't just assume the CYA is at my target level!

    Thanks,
    Garry
    Above-Ground Pool 24' x 52" (13,500 gal)
    Installed May 2011
    Hayward 1HP Power-Flo Pump. Hayward 150lb Sand Filter, Main drain
    Plumbed with Flexible PVC & Fittings June 2013, Modified Slotted Return Jet for Increased Circulation (2014)

  2. Back To Top    #2

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    Re: CYA Added, But Testing Week Later Shows Little Rise

    I would trust your CYA testing method because the pool is using too much chlorine and you are measuring low CYA. Your 10 ppm assumption might have been off, could have been zero and now you only bumped it up to 25, barely readable on the test. Get some more CYA and add enough for about a 10-15 ppm rise.

    Make sure the CYA is not coming out of the panty hose, a few hours does seem to be a short time for it to dissolve. There have been reports of some CYA not working like it should, but the shelf life is very long if properly stored. Twice I used some CYA that I got from Lowes and it only raised it by 1/4 of what it should have.
    16k gal plaster with raised spa, Jandy DEV60 filter, 2 HP 2-speed SHPF Jandy Stealth pump
    Hayward Aqua Rite T-15 SWCG, Jandy LXi 400k BTU NG heater, 350 sq.ft. of Sun Star solar panels, TF-100 Test Kit, Dolphin s300i Cleaner
    Test Kits . Pool Math . Chlorine/CYA Chart . The SLAM Process

  3. Back To Top    #3

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    Re: CYA Added, But Testing Week Later Shows Little Rise

    Well since I just added more CYA this past Saturday (enough to raise another 19ppm) I guess I really have to wait until this coming Saturday to test again. I thought it would be best to put off buying more CYA until next year (so it's more fresh), but if I need more after my 3rd test I'll go ahead and get it. It won't be the same brand I'm using now either (I no longer support the pool store it came from).

    When I said "few hours" it might have been 4 or 5 hours. Or I could possibly be confusing it with the borax I'm adding by the same method (although that stuff comes out of the panty hose really quick it seems - maybe an hour or less).

    Funny thing is, I don't remember having such a hard time with CYA last year. I believe I only added it once and it tested within reason of my expected target and I never touched it the rest of the season.

    EDIT - And how long is the TF Testkits CYA test reagent good for? 2 or 3 seasons I hope? (I did buy fresh Cl & pH reagents this year and determined my old ones which were on their 3rd season were reading higher than with the new reagents (not too much higher, about 1ppm for Cl and about .1 for pH).

    Thanks,
    -Garry
    Above-Ground Pool 24' x 52" (13,500 gal)
    Installed May 2011
    Hayward 1HP Power-Flo Pump. Hayward 150lb Sand Filter, Main drain
    Plumbed with Flexible PVC & Fittings June 2013, Modified Slotted Return Jet for Increased Circulation (2014)

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    Jenischmeni's Avatar
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    Re: CYA Added, But Testing Week Later Shows Little Rise

    Ironic....

    I've been adding CYA and when I test a week later, it's not going up nearly as much as it should! My chlorine levels are holding reasonably well but I have a SWG that is constantly making chlorine.

    I'm trying to raise it from 30 -70 and am attacking it a little less aggressive as I don't want to overshoot the target.

    I attributed it to the stabilizer that I bought from Menards. (Figuring, "You get what you pay for"!)

    Great to read that someone else is seeing that too.
    Central Indiana, 7200 gallon, IG fiberglass, L250 Jacuzzi sand filter, Hayward H150 gas heater, Pentair fiber optic light - installed '06. AOSmith 1.0hp pump, CPSC-24 SWG - installed '13. TF-100 Test Kit.

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    Re: CYA Added, But Testing Week Later Shows Little Rise

    Woohoo! Finally my Chlorine is holding up! I raised it to 6 (might have really been 7) yesterday afternoon and just checked now at 5 to 6 (my test kit only goes to 5). So something must be going right! My pH keeps dropping, but I think that's fairly normal. About every week I have to raise it from 7.3 (maybe 7.2) up to 7.8. My TA is at 100 too. I think this matches last season pretty well.

    -Garry
    Above-Ground Pool 24' x 52" (13,500 gal)
    Installed May 2011
    Hayward 1HP Power-Flo Pump. Hayward 150lb Sand Filter, Main drain
    Plumbed with Flexible PVC & Fittings June 2013, Modified Slotted Return Jet for Increased Circulation (2014)

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    Mod Squad jblizzle's Avatar
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    Re: CYA Added, But Testing Week Later Shows Little Rise

    The CYA reagent is inert, so it will last for a long time ... still should store it in a cool dark place with all the other reagents.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
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  7. Back To Top    #7

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    Re: CYA Added, But Testing Week Later Shows Little Rise

    Well the shed that I keep the reagents in does get very hot inside (little to no ventilation inside). I'd hate to store them anywhere else though as it's so convenient. I do plan on adding vents though.
    -Garry
    Above-Ground Pool 24' x 52" (13,500 gal)
    Installed May 2011
    Hayward 1HP Power-Flo Pump. Hayward 150lb Sand Filter, Main drain
    Plumbed with Flexible PVC & Fittings June 2013, Modified Slotted Return Jet for Increased Circulation (2014)

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    Mod Squad jblizzle's Avatar
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    Re: CYA Added, But Testing Week Later Shows Little Rise

    Well, that is certainly not good for the other reagents to be in the heat. It is usually best to do the testing inside the house anyways, so why not keep the kit there in a closet?
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
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  9. Back To Top    #9

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    Re: CYA Added, But Testing Week Later Shows Little Rise

    Well, my pool is about 100 feet behind the house up a slope. We have a pavilion with an attached "shed" on the end. I just get tired of walking up and down the slope. I know, I know, I'm lazy!

    -Garry
    Above-Ground Pool 24' x 52" (13,500 gal)
    Installed May 2011
    Hayward 1HP Power-Flo Pump. Hayward 150lb Sand Filter, Main drain
    Plumbed with Flexible PVC & Fittings June 2013, Modified Slotted Return Jet for Increased Circulation (2014)

  10. Back To Top    #10
    Mod Squad jblizzle's Avatar
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    Re: CYA Added, But Testing Week Later Shows Little Rise

    Walking from the house to the pool to get a large water sample and back to the house to test is the same amount of walking as going from the house to the pool, doing the test, and then walking back to the house
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  11. Back To Top    #11

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    Re: CYA Added, But Testing Week Later Shows Little Rise

    Ok, I rechecked CYA yesterday (about 1 week after adding my second dose of CYA) and I get a reading of somewhere between 28 and 30. It's a little lower than I would like, but I am out of CYA and don't want to buy it again unless I need it. My Chlorine levels have been holding pretty steady now, losing about 1ppm per day. Pool is crystal clear!

    -Garry
    Above-Ground Pool 24' x 52" (13,500 gal)
    Installed May 2011
    Hayward 1HP Power-Flo Pump. Hayward 150lb Sand Filter, Main drain
    Plumbed with Flexible PVC & Fittings June 2013, Modified Slotted Return Jet for Increased Circulation (2014)

  12. Back To Top    #12

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    Re: CYA Added, But Testing Week Later Shows Little Rise

    16k gal plaster with raised spa, Jandy DEV60 filter, 2 HP 2-speed SHPF Jandy Stealth pump
    Hayward Aqua Rite T-15 SWCG, Jandy LXi 400k BTU NG heater, 350 sq.ft. of Sun Star solar panels, TF-100 Test Kit, Dolphin s300i Cleaner
    Test Kits . Pool Math . Chlorine/CYA Chart . The SLAM Process

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