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Thread: Calcium ring - where did that come from?

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    Calcium ring - where did that come from?

    This is my first pool and I've had it 2.5 years. When we bought the house there was a calcium ring already on the tile and the pool hadn't been well maintained. We drained and refilled. With the help of this site I have had zero issues with the water and the chemicals always seemed to be in check.

    Earlier this week my auto-leveler quit working - it was running non-stop. I turned off the water to it and decided I would fix it this weekend. Over the past few days the pool level dropped a couple of inches. Given how high it was that needed to happen. I go out tonight to run a full chemical test and I see a nasty white ring around the entire border. Last year we slowly went the pumice stone route and we seemed to have the ring gone. I was surprised and unhappy to see it return this afternoon.

    I'm unsure of what I did wrong. I saw nothing for over a year and then, BOOM, ring. Could the ring have been underneath the normal water level? Do I not have my chemicals where they need to be? Is my calcium hardness getting too high for a rookie to maintain? My pH does tend to wander up and my CYA loves to drop (I'm low again). My calcium hardness has increased steadily since we filled the pool, going from 325 at fill to 850 now. Chlorine stays very stable. Any advice appreciated.

    Test results from this afternoon:
    20K pool (SWG)
    FC: 4.5
    CC: 0
    CH: 850
    CYA: 40
    TA: 70
    Salt: 3100
    Borates: 60 (no idea how this is over 50...may just be reading the strips wrong)
    Pool temp: have not seen it over 93 but I don't run my pump in the afternoon

    Now that's I've typed all of this out I see temperature has a pretty big impact on CSI (pool math). I've been trying to keep my pH between 7.6 and 7.8 Should I be keeping it lower than that?
    19K PebbleTec in-ground with spa, Hayward Super II pump, DE 60 series filter, T-15 SWG
    Water feature, Hayward Northstar pump

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    Mod Squad pooldv's Avatar
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    Re: Calcium ring - where did that come from?

    Need to keep CSI between -0.3 and 0 to prevent scale. With CH that high you could even drop it to -0.6 and let it drift back up to -0.3 for some extra cushion. You should be able to manage CH up to at least 1000, quite a few other folks here do. Highest I've seen is 1200 or so. You can drop TA to 60 or even 50 to see if that helps to slow pH rise.

    More here, Pool School - Calcium Scaling
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    Re: Calcium ring - where did that come from?

    Thank you for the quick reply. I did not realize I should be keeping it below 0.0 to avoid that, nor did I realize the temperature had such a big impact on it.

    Getting my TA down is going to be a real pain but I will work harder at it. pH rise has been the only real battle I've had with the chemicals and it only meant I had to check it every day and usually add acid every two or three days.

    Does this sound like the proper approach?
    Get my CYA back to 80 (I started this tonight and need to keep a closer eye on it)
    Keep my pH between 7.4 and 7.6 (even a bit lower as I aerate)
    Do whatever I can to get my alkalinity down to 60

    Is there anything else I can do other than wait for winter?
    19K PebbleTec in-ground with spa, Hayward Super II pump, DE 60 series filter, T-15 SWG
    Water feature, Hayward Northstar pump

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    Re: Calcium ring - where did that come from?

    You noted "My calcium hardness has increased steadily since we filled the pool, going from 325 at fill to 850 now. Chlorine stays very stable."

    Is this a newer pool filled this year?


    Valley of the Sun, Arizona.....10k gunite/pebble (Re-surface March 2015) w/in floor Caretaker 99 cleaning heads -- Pentair FNS 60 DE filter -- Pentair IntelliFlo Variable Speed for pool -- Pentair Wisperflo 1 HP for boulder waterfall...Taylor K-2006 & Taylor K-2006C kits

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    Re: Calcium ring - where did that come from?

    Quote Originally Posted by oldguy70 View Post
    You noted "My calcium hardness has increased steadily since we filled the pool, going from 325 at fill to 850 now. Chlorine stays very stable."

    Is this a newer pool filled this year?


    The pool is eight years old, drained and filled 2.5 years ago. I may not have the fill number correct but I know it was relatively high for water out of the hose.
    19K PebbleTec in-ground with spa, Hayward Super II pump, DE 60 series filter, T-15 SWG
    Water feature, Hayward Northstar pump

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    Mod Squad pooldv's Avatar
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    Re: Calcium ring - where did that come from?

    No real need to work at lowering TA if you don't want to. It will lower on its own slowly as you add muriatic acid to lower PH.

    Yes, get CYA back to 80. You'll probably lose 5ish ppm of CYA per month during summer. 80 protects FC noticeably better than 70.
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    Re: Calcium ring - where did that come from?

    Quote Originally Posted by pooldv View Post
    No real need to work at lowering TA if you don't want to. It will lower on its own slowly as you add muriatic acid to lower PH.

    Yes, get CYA back to 80. You'll probably lose 5ish ppm of CYA per month during summer. 80 protects FC a noticeably better than 70.
    I actually do want to get the TA down. I thought I had it where I wanted when I added borates last year but I wish I hadn't added them now. Might be time to fire up the super aerator I cobbled together last year.

    Thank you for you help. I appreciate it.
    19K PebbleTec in-ground with spa, Hayward Super II pump, DE 60 series filter, T-15 SWG
    Water feature, Hayward Northstar pump

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