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Thread: How long until CYA registers on test....

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    Join Date
    Jul 2013
    Location
    Chicago IL
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    83

    How long until CYA registers on test....

    In Chicago here we got a heatwave . I noticed my pool been tearing through chlorine ... Did a CYA test with TF100 came up 0, i could clearly see the black dot filling all the way up the tube.... Added 16oz of stabilizer per pool calculator in a sock over the return. I test water today , same 0 ... Does it take a while for stabilizer to register on cya test? .. I would hate to keep adding stabilizer to find out i added too much.
    15ft Round, Above Ground , Rheem 106K Heater , Black Diamond 90 Cartridge Filter, Pool Frog(disconnected) ,TF-100, City of Chicagos finest H20

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    Join Date
    Aug 2013
    Location
    Arab, Alabama
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    Re: How long until CYA registers on test....

    It can take up to a week to register. Just assume your CYA is at the calculated level.
    39YO 13K gallon former SWAMP/MONEY PIT, concrete bottom/Fiberglass Walls, Ecotech VS pump, Hayward Sand Filter, Dolphin DX5 Plus, Loop-Loc safety cover and YES, I have a TFT-100 test kit!

    Shock Level and Maintain - CL/CYA Chart

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    Join Date
    Jul 2013
    Location
    Chicago IL
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    Re: How long until CYA registers on test....

    All i needed ... Thanks again
    15ft Round, Above Ground , Rheem 106K Heater , Black Diamond 90 Cartridge Filter, Pool Frog(disconnected) ,TF-100, City of Chicagos finest H20

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    JoyfulNoise's Avatar
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    May 2015
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    Re: How long until CYA registers on test....

    The technical answer is - it depends on how you add it.

    The 5-7day rule of thumb came into being because people would often add CYA granules directly to their skimmer baskets where it would get sucked into the filter and dissolve very slowly. Since the filter has a fairly large surface as compared to a pipe, the linear flow rate of water through the filter is much slower and therefore that would affect how quickly the CYA would dissolve. CYA also has a tendency to break up into smaller and smaller particulates before fully dissolving and dispersing into solution unlike salts or acids which dissociate rather quickly in water.

    A poor analogy would be like the difference between a teaspoon of sugar and a teaspoon of salt in room temperature water. If you add salt, it may pile up in a lump on the bottom but it will dissociate and disperse quickly into the water volume and the water will become salty. If you add a teaspoon of sugar to water, it will settle to the bottom and remain there; it's dispersion is much slower. You can then draw water off the top of the glass and you'll barely be able to taste the sugar. CYA is a lot like sugar - it take a while for it to get hydrated and disperse. The other technical way to look at it is to look up the solubility of CYA. It is quite low at 27mg per liter of water which you can contrast with salt that has a solubility of 359 grams per liter.

    That being said, if you use the sock in front of the return method, then the CYA should dissolve and disperse fairly quickly and evenly (especially if you brush your pool while it is dissolving) and should be detectable within 24 hours. There's nothing magical about the chemistry, it is simply a matter of the CYA effectively dispersing into the pools water volume and that's all controlled by turn-over rate and water agitation. As an example, I often put socks of CYA into my skimmer with just a few squishes by hand and the socks are depleted within 24 hours (I always keep the pump running when I do this and I'll usually give the pool a good brush down or have the kids splash around in it for a while). By the next day after I pull the empty socks out, I can easily detect the CYA increase in the melamine test.
    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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