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Thread: Stabilizer Level Increases Significantly While Adding Only a Small Amount of CYA????

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    Stabilizer Level Increases Significantly While Adding Only a Small Amount of CYA????

    Eight year old 22,500 gallon pebble finish gunite pool in Massachusetts with DE filter and heat pump. On 6/12/2016 the stabilizer level was 51 ppm. On 8/15/2016 it was 70 ppm. And on 8/29/2016 it measured 84 ppm. The first and last tests were performed by the same pool place; the middle result was done by a different pool place. During that time, I added just six 3-inch trichlor pucks when I was away for 8 days. The rest of the chlorine came from 8% sodium hypochlorite bleach.

    So how can my cyanuric acid level rise so much when I've hardly added any stabilizer? I would expect the CYA level to rise maybe 7 or 8 ppm based on the CYA content of the pucks. I have stayed away from trichlor because I wanted to keep the cyanuric acid level relatively low. The only other chemicals I add are muriatic acid and sodium bicarbonate. Can these test results be accurate? What is going on here?

    Please ignore the pool information immediately below--it somehow gets attached to my posts.
    40 year old, 16,000g, plaster, in ground pool with 150gpm cartridge filter and 1.5hp pump.

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    Mr Bruce's Avatar
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    Re: Stabilizer Level Increases Significantly While Adding Only a Small Amount of CYA?

    I think you have discovered why pool store testing is terrible first hand.

    There is a link to test kits in my signature!
    32K gallon Plaster - 1hp Hayward 2 speed Super Pump - Hayward S200 Sand Filter - TF100XL
    Test Kits - Pool Math - Chlorine/CYA/Target/Slam Chart

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    pabeader's Avatar
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    Re: Stabilizer Level Increases Significantly While Adding Only a Small Amount of CYA?

    Your results are exactly why we don't recommend pool $tore testing. You can take the same sample to the same store three times in a row and you'll get four different answers.

    You really need to get your own kit. Either a TF-100 or a K-2006C
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

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    JoyfulNoise's Avatar
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    Stabilizer Level Increases Significantly While Adding Only a Small Amount of CYA????

    Buy a high quality test kit like the ones we recommend here (you can get any of them on Amazon from a variety of different vendors not associated at all with this site) and you'll never have to ask the question you just posted ever again.

    The answer to your question is - we don't know either...pool store testing is so inaccurate that we have no idea what your CYA level is. Could be the first number, 51ppm or the last number, 84ppm. No way to know.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Stabilizer Level Increases Significantly While Adding Only a Small Amount of CYA?

    OK, so I own a K-2006 test kit. I remember doing the CYA test a number of years ago and thought it was pretty hokey. I thought the "disappearing dot" aspect was too subjective. Plus, the numbers for CYA are very difficult to read; clear plastic numbers on a clear plastic background, on an inside corner of the test fixture--bad design.

    Since it doesn't seem there is anything better out there I thought I'd give it another try. I had to wash the inside of the tube directly over the black dot. I ran the test a few times (dumping out some of the mixture and adding back more) and got readings in the 45 to 50 ppm range. I'm reasonably confident in those results, so I guess I'll go with them! Thanks.
    40 year old, 16,000g, plaster, in ground pool with 150gpm cartridge filter and 1.5hp pump.

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    Mod Squad pooldv's Avatar
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    Re: Stabilizer Level Increases Significantly While Adding Only a Small Amount of CYA?

    This view tube is much better. TFTestkits.net CYA view tube

    When in doubt pour the sample back and forth as many times as you want and walk around to different light. Also, always round up. An extra couple of ppm won't hurt a thing and aiming low leaves little room for error. Remember, it is safe to swim above minimum and up to shock level for your CYA, FC/CYA Chart. There is a lot more room between target and shock level then there is between minimum and target.
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    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

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    JoeSelf's Avatar
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    Re: Stabilizer Level Increases Significantly While Adding Only a Small Amount of CYA?

    And the CYA test is done outdoors with the sun at your back.
    13700 gal, 32'x16'x54" AG oval, vinyl, Echo Canyon II, 8500 series, Narrow Yard, Safety Fence & Stair, Sta-Rite Crystal Flow T-210WF, 44 GPM, Hayward SP1580TL 1HP Pump, Aqua Luminator, Festiva wedding cake steps, March 2006, TFT-100, Speed-Stir, Sample Sizer. Avatar Credit: TJ Townsend

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