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Thread: Which test to believe?

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    Join Date
    May 2009
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    Kennewick, WA
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    Which test to believe?

    I am using a Walmart HTH brand test kit until my TF-1000 arrives. I took a sample to the pool store last week for a more accurate reading, but the difference seems to be to much. I wanted to add borates, but now I don't know if my TA is in line.

    Pool Store said last week:
    TC 1.3
    FC 1.3
    PH 7.4
    TA 75
    TH 330
    CYA 61

    Walmart test says today:
    FC 1
    PH 7.8
    TA 90-100
    CH 410
    CYA <30 (the drop disappeared just a few drops above the 30 line, the top of the bottle)

    Do I need to lower the TA more before borates?
    Is the CH too high? I don't want to replace the water after the borates. (I have a vinyl liner)
    How much chlorine do I use? Thats a big spread for the CYA.
    18x18 Round AG, 8000 Gallons, PacFab Superflow PF-50 200 lb Sand Filter (new sand), 3/4 hp Magnatek Centurian
    BBB Method

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    Guest

    Re: Which test to believe?

    How is the pool store testing? Their 75 ppm for CYA suggests either strips or reagent vials being read by a photometer or colorimeter. For TA and CYA these tests are not necessarily better or more precise than the one in your kit! (I won't bore you with the technical reasons.)

  3. Back To Top    #3

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    Re: Which test to believe?

    I don't know what the pool store used for each test. They have Bioguards Alex software and a combination of a wet lab and strip reader. I'm not sure what tests were done with the lab and what was done with the reader.

    It sound's like I should go ahead and up the CYA?

    Is my CH too high? I'm not sure if I should worry or not. We do have hard water in this area, but I'm sure a big part of it is all the cal-hypo I used last year.
    18x18 Round AG, 8000 Gallons, PacFab Superflow PF-50 200 lb Sand Filter (new sand), 3/4 hp Magnatek Centurian
    BBB Method

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    JasonLion's Avatar
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    Re: Which test to believe?

    Test strips, even when read by an electronic strip reader, can be amazingly inaccurate. I would trust the WalMart kit over test strips every time.
    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

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    frustratedpoolmom's Avatar
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    Re: Which test to believe?

    Quote Originally Posted by tanikir

    It sound's like I should go ahead and up the CYA?

    Is my CH too high? I'm not sure if I should worry or not. We do have hard water in this area, but I'm sure a big part of it is all the cal-hypo I used last year.
    CH is high, but you can control problems by keeping your PH at 7.6, and never above 7.8. I would assume if your refill water is lower, the number will gradually drop over time thru backwashing.

    As for the CYA, I suppose it wouldn't hurt to bump it up 10ppm to 40, until you can test with your TF100. That way if its really higher, you haven't done too much damage and backwashing will slowly drop it anyway. Refer to the CYA chart for your recommended chlorine levels.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  6. Back To Top    #6
    Guest

    Re: Which test to believe?

    Quote Originally Posted by tanikir
    I don't know what the pool store used for each test. They have Bioguards Alex software and a combination of a wet lab and strip reader. I'm not sure what tests were done with the lab and what was done with the reader.

    It sound's like I should go ahead and up the CYA?

    Is my CH too high? I'm not sure if I should worry or not. We do have hard water in this area, but I'm sure a big part of it is all the cal-hypo I used last year.
    The ALEX system is notorious for inaccurate results. I would not trust it as far as I could throw it. The syetem is designed to sell as many chems as possble for Bioguard dealers! It uses test strips for most of the tests. Trust your HTH kit!

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    Re: Which test to believe?

    Quote Originally Posted by JasonLion
    Test strips, even when read by an electronic strip reader, can be amazingly inaccurate. I would trust the WalMart kit over test strips every time.
    Maybe that's why they said I shouldn't worry about the CYA until it's over 200!
    18x18 Round AG, 8000 Gallons, PacFab Superflow PF-50 200 lb Sand Filter (new sand), 3/4 hp Magnatek Centurian
    BBB Method

  8. Back To Top    #8
    Guest

    Re: Which test to believe?

    Quote Originally Posted by tanikir
    Quote Originally Posted by JasonLion
    Test strips, even when read by an electronic strip reader, can be amazingly inaccurate. I would trust the WalMart kit over test strips every time.
    Maybe that's why they said I shouldn't worry about the CYA until it's over 200!
    Actually thaat is the coperate stance for all the Chemtura companies. Chemtura is one of the worlds largest manufacturers of trichlor and dichlor products and their brands include Bioguard, Guardex, Sun, Omni, Pooltime, and Aquachem just to name a few of them. There are many more.
    I have actually been told this on the phone by Chemtura techs!

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    Bob_Funk's Avatar
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    Re: Which test to believe?

    either result with your cya-get your chlorine up
    I consider myself very lucky I found this site before the pool store found me-pool owner since Nov 2008- Stunningly clear 17,000 gal fiberglass pool, thanks to this site, installed in 1982-24" 3.1sq. ft sta-rite sand filter, 1 hp - 2 speed wisperflo pump-WFDS-4

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