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Thread: CYA Loss

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    Join Date
    Mar 2014
    Location
    Mesquite, Texas
    Posts
    29

    CYA Loss

    I'm telling myself I've graduated from "Just Getting Started"....to "Testing and Balancing Water"....

    I've been using the TF-100 and managing the pool since a renovation in April 2014 (that was the fill date). I just tested the water with the following results:

    FC 5.5
    CC 0
    TC 5.5
    PH 7.8
    CYA 25
    CH 325
    ALK 60
    Borates - 50

    Pool crystal clear

    I don't understand why the CYA has dropped When I filled the pool in April, I got it up to 40 and have been chlorinating it to maintain 6 (yes, that is a tad higher than recommended (Chlorine/CYA chart) but I am in Texas and the pool is in full sun all day and I'd rather be safe than sorry (then letting it drop below 3 before I get home from work).

    Anyway this morning, I've tested the CYA over and over and it's 25. We have had about 8 inches of rain since April and I've had to drain off about 6 inches since that time and have had to add about 4 inches due to dry spells and evaporation.

    I'm nervous that I am over-analyzing that black dot in the CYA test tube, or perhaps have under analyzed it these past few months. I'm scared to add stabilizer because I don't want to jack it up to much so I'm thinking I will put pucks in the chlorinator and just test the CYA daily until it's up to 40.

    Can it drop like that?
    14K IG Aggregate Mini Pebble, 1 HP Hayward Single Speed Pump 120 GPM, 175 Sqft Cartridge Filter
    In-Line Chlorinator, 360 Polaris Black Max, Sheer Descent Water Feature. TF-100 Test Kit
    Build Date 2/1994; Remodel Date 4/2014; Original Owner, North Texas

  2. Back To Top    #2
    Mod Squad woodyp's Avatar
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    Apr 2010
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    Re: CYA Loss

    Suggestion: When you do the cya test, pour the sample back into the red capped bottle then back into the measuring vial a couple of times to get a good "eyeball" check average.
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
    2 Speed Hayward Power-Flo Matrix 85 g.p.m. 22" 250lb. sand filter hard plumbed
    Pool Rover Jr., Pool Blaster Max, Diver Dave TF100 Test Kit/Speed Stir
    Margaritaville Frozen Concoction Maker, Liqour Chiller, & Drink Mixer & Party Tub----Collect 'um all!

  3. Back To Top    #3

    Join Date
    Mar 2014
    Location
    Mesquite, Texas
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    Dropping Alkalinity

    Trying to keep my threads separate.

    Since I have new plaster, I am aware that PH can fluctuate for up to a year. It ranges from 7.2 (after I add acid) and slowly creeps back up to 7.8 -- which is ideal, but it seems like if I let it get to 7.8 and I don't add acid, it is up to 8.2 in a matter of days so I try and add acid when it gets to 7.8.

    I don't understand why alkalinity would fluctuate though. My alkalinity is 60 this morning, I think I adjusted it ab out two weeks ago from 60 to 90...so a loss in two weeks. Would substantial rain and subsequent draining of the pool (because water has reached the coping), also affect the alkalinity?

    Just curious as to the chemistry of all that.
    14K IG Aggregate Mini Pebble, 1 HP Hayward Single Speed Pump 120 GPM, 175 Sqft Cartridge Filter
    In-Line Chlorinator, 360 Polaris Black Max, Sheer Descent Water Feature. TF-100 Test Kit
    Build Date 2/1994; Remodel Date 4/2014; Original Owner, North Texas

  4. Back To Top    #4
    JasonLion's Avatar
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    37,879

    Re: CYA Loss

    CYA does go down very slowly over the course of the season. Between that and the water replacement, it could easily have gone down 5, but 15 seems very unlikely. However, the test is +-15, so you are well within the precision of the test.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  5. Back To Top    #5

    Join Date
    Mar 2014
    Location
    Mesquite, Texas
    Posts
    29

    Re: CYA Loss

    Thank you. Based on this reply, I'll leave it alone.
    14K IG Aggregate Mini Pebble, 1 HP Hayward Single Speed Pump 120 GPM, 175 Sqft Cartridge Filter
    In-Line Chlorinator, 360 Polaris Black Max, Sheer Descent Water Feature. TF-100 Test Kit
    Build Date 2/1994; Remodel Date 4/2014; Original Owner, North Texas

  6. Back To Top    #6
    Butterfly's Avatar
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    May 2007
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    South Carolina
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    Re: CYA Loss

    Scroll down to Post #8 the see "Notes" section: http://www.troublefreepool.com/threa...Kit-Directions
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

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  7. Back To Top    #7
    Divin Dave's Avatar
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    Oct 2013
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    Re: Dropping Alkalinity

    There are a few reasons why TA might drop, but probably the reason in your case is because of additon of so much MA while maintaining your new plaster.
    Adding MA to drop PH also drops TA.

    Once your plaster evens out over time, the TA will become more stable as the PH does.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
    www.tftestkits.net Experience- it's what's learned just after you needed it most !!

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    In the Industry

    duraleigh's Avatar
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    Re: CYA Loss

    I have merged your threads. It is really hard for frequent responders to keep up when you have multiple threads going. Keep everything under this one for us.....we'll get you lot's of help!
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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