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Thread: Can CYA ever drop on its own? Or is my new CYA reagent different somehow?

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    Join Date
    Jul 2013
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    St Louis, Missouri
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    Can CYA ever drop on its own? Or is my new CYA reagent different somehow?

    Hey everyone!

    Still humming along in my first year using the TroubleFree method. Thanks to you all.
    i have a question about my CYA level dropping 10 points.

    i had to drain the pool several times at the beginning of the season to get my CYA down to 50. (from 100!)
    Then, satisfied with 50, i've been operating with it at that level for most of the season.
    Plus i hadn't even been testing the CYA the last 2 months or so, because i ran out of the R-0013 CYA reagent, and am no longer using chlorine pucks.

    i recently bought some more reagent.
    So, this morning (after a couple months or so) i tested the CYA and got a 40.

    Now this puzzles me because i haven't been draining the pool since i tested at 50.
    i did drain the filter twice this year so i could clean it out, but i wouldn't have thought that'd be enough to affect the 11,813 gallon pool.
    We've also gotten a bit of rain this year, but as i said, i haven't been draining it.

    i thought once CYA is in your water, it's there to stay.
    Could my new refill R-0013 reagent be reading differently?
    i mean granted, that test is kind of funky, but i'm... sort of confident i did it right.
    At the very least, i know i did it the same way as before.

    Latest test if that matters
    FC - 6
    CC - 0
    TA - 90
    CH - 250
    CYA - 40
    pH - 7.5

    Any ideas?
    i guess i'm looking a gift horse in the mouth. Maybe i should just be happy it's down!
    Size: 11,813 gallons
    Inground Surface: Pebble/Gunite Installed: 2009 (St. Louis, MO)
    Filter: Cartridge Sta-Rite S7M120, Flow Rate: 50-80 GPM
    Pump: 1hp Max-E-Pro
    Accessories: Polaris 380 cleaner, Sta-Rite Heater SR333k, Hayward CL220 Chlorinator

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    pwrstrk's Avatar
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    Aug 2012
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    Elverson Pa.
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    Can CYA ever drop on its own? Or is my new CYA reagent different somehow?

    Your fine. You will lose a couple of ppm per month along with backwashing the filter, splash out and the rain filling it back up will change things.
    You should test it once a month to see where it is. That's what I do and I just had to add some as mine was down to 30. I keep mine at 40. 😎
    Jeff
    24'x54" AG Morada RTR (by wilbar) 13'500 gal. Hayward Powerflo Matrix 1hp 2 speed. Hayward Perflex EC65 DE filter.

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    May 2011
    Location
    Los Angeles, CA
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    Re: Can CYA ever drop on its own? Or is my new CYA reagent different somehow?

    Remember that the CYA test is accurate +/- 15 anyways...
    Suley, West Hills, CA
    IG 23000 Gallons with IG Spa Gunite plaster, Pentair Intelliflo VS 3HP, Pentair Clean & Clear Plus 420 Cartridge filter, Teledyne Laars One series 400,000 BTU Nat Gas Heater, Hayward Max Flo 1HP Single Speed Spa pump, Noisy Spa blower, Dolphin Deluxe 4 robotic vacuum.

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    Mod Squad tim5055's Avatar
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    Re: Can CYA ever drop on its own? Or is my new CYA reagent different somehow?

    I'm going to say that a 10 point drop in a couple of months is not unusual with backwashes, splash out and rain filling the pool.
    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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    Join Date
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    Location
    St Louis, Missouri
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    Re: Can CYA ever drop on its own? Or is my new CYA reagent different somehow?

    Ok cool. i will assume it actually is at 40 then.

    You guys keep mentioning backwashing.
    I think with my setup i can't do that. The pump only flows one way.
    What i do is drain the filter tank, open it up, pull out the cartridges, and hose 'em off.

    Does that change your answers?
    Size: 11,813 gallons
    Inground Surface: Pebble/Gunite Installed: 2009 (St. Louis, MO)
    Filter: Cartridge Sta-Rite S7M120, Flow Rate: 50-80 GPM
    Pump: 1hp Max-E-Pro
    Accessories: Polaris 380 cleaner, Sta-Rite Heater SR333k, Hayward CL220 Chlorinator

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    Mod Squad jblizzle's Avatar
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    Re: Can CYA ever drop on its own? Or is my new CYA reagent different somehow?

    You are right. You do not backwash cartridge filters ... which is what your signature says
    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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    Join Date
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    Boca Raton, FL
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    Re: Can CYA ever drop on its own? Or is my new CYA reagent different somehow?

    You can always pick up a bottle of R-7065 CYA Standard Solution at tftestkits. This will allow you to test your reagent and your testing skills against a standard 50ppm CYA solution. I would do that before I assume my 30 ppm test results were really 40 ppm.
    16x32 DiamondBrite kidney, 12,500 gal. (circa 1985) 3/4hp Hayward SII, Harmsco BF84, Taylor K-2006, Hayward SwimPure Plus / Tcell-15
    Boca Roton, Fl. USA.

    prior 17k gal. vinyl, Sand filter

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