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Thread: New Pool Owner Calc Hardness Seems High

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    New Pool Owner Calc Hardness Seems High

    Hi Everyone,

    I just bought a new house with a pool, first pool I've ever owned. The previous owner used a chemical service, and apparently they came once a week. From what I can tell, they basically add CYA twice per year, and liquid chlorine every week. All that for $50 per month - what a deal, wink wink.

    Some things I've noticed about the pool, the water looks pretty clear to me. No obvious signs of algae or anything. Around the waterline tile, there is some white scaling.

    I've been reading a lot here for the past week or so, read through Pool School, and just got a Taylor K-2006 test kit today. Here's what I tested:
    25k gal, In ground, plaster, North Texas
    Water Temp: 76
    FC 17.5
    CC 0
    pH 7.6
    TA 140
    CH 370
    CYA 85

    I was surprised at the FC so I retested it and got the same thing.

    My first thought is that the CH is too high and is the cause of the scaling. From what I've learned, I should lower the pH by adding muriatic acid and I think this would then bring the CH down?

    I plan to take a sample to Leslies in the morning to see if they get the same readings I got above.

    Thanks in advance,
    Rob
    23,000 IG Plaster pool w/ spa, Pentair FNS Plus 48 DE Filter, Hayward RS1000 Main pump, Polaris booster pump, CPSC48 SWG, Legend pool sweep. Dallas, Texas, Full sun, Taylor K-2006

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    Join Date
    May 2011
    Location
    Clearwater, FL.
    Posts
    446

    Re: New Pool Owner Calc Hardness Seems High

    Hi rdhetrick and welcome to TFP!
    If you do go to the pool store, take what they say with a grain of salt. (Don't trust pool stores)
    You have a Taylor drop based system. Taylor kit reagents are the best in the industry and is the same reagents comes in the TF-100 kits from tftestkits.net, which is what most of us use here for testing.

    Stay with your results, just re-read the newer testing instructions here:
    extended-test-kit-directions-t25081.html

    A speed-stir is also a great addition to your test kit. I love mine.
    Get familiar with the pool calculator.
    Plug in your numbers and check your csi for plaster pools.
    See the recommended levels here in Pool School:
    pool-school/recommended_levels
    Some of the other more experienced members will probably chime in.

    Chuck
    Swim n Play 21' round, expandable 72" liner, 6FT deep center, buried 14", 12,750 Gallons
    Waterway 1HP-2 speed with 22" Sand filter
    TF-100 test kit
    Thanks to TFP my pool is perfect all the time :party:
    I now suffer from Sparklypoolitis! :whoot:
    I am a Platinum contributor because I want everyone who comes here to Trouble Free Pool to have the same success that I enjoy with my pool and family.

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    linen's Avatar
    Join Date
    Jul 2010
    Location
    Twin Cities, MN
    Posts
    8,649

    Re: New Pool Owner Calc Hardness Seems High

    Welcome to tfp, rehetrick

    Quote Originally Posted by rdhetrick
    I was surprised at the FC so I retested it and got the same thing.
    How were you measuring FC prior to the taylor kit? What is your method of chlorination?

    Quote Originally Posted by rdhetrick
    My first thought is that the CH is too high and is the cause of the scaling. From what I've learned, I should lower the pH by adding muriatic acid and I think this would then bring the CH down?
    It will not bring CH down, that can only be done by drain/refill cycles or reverse osmosis (RO) treatments. What is the CH and TA of you fill water?

    Have you plugged your numbers into the poolcalculator.com com yet? The calculator has a calculation called CSI. The guideline is if your csi is 0.6 or higher, then you are at risk for calcium scaling. I get 0.35 for your pool with your numbers, but if I put in 8.0 for ph, then I get 0.74 csi. So yes, keep your ph lower for not (down to 7.2) and not above the current 7.6 to prevent more[/url]scaling. Lowering you TA down to below 90 will also help. Play with the calculator, it will show you what is good and bad for csi.

    Your cya level is also quite high at 85. We recommend 30-50 ppm for a bleach/liquid chlorine pool. You might be able to live with 85, but you will need to keep your FC minimum level higher...see:http://www.troublefreepool.com/pool-...ya_chart_shock Only way to lower is to drain/refill or RO.

    Quote Originally Posted by rdhetrick
    I plan to take a sample to Leslies in the morning to see if they get the same readings I got above.
    I would trust your readings and not mess with the pool store.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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