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Thread: My Weekly test, Add or not add

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    Chula Vista 45k's Avatar
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    My Weekly test, Add or not add

    Good morning everyone. I plugged my weekly test results into pool math and it is telling me to add baking soda, 423 oz.

    CL 5-10
    PH 7.2
    FC 10 (Just added last night after heavy use over the weekend)
    CC 0
    TC 10
    CH 1000 ( I need to drain when possible)
    TA 60
    CYA 60

    I was told not to add the baking soda in another thread, but I am confused. If pool math is telling me to do it, why shouldn't I?
    45k, IG,Plaster, Pentair FLT FNS PLS 60 DE, A.O. Smith 1hp square flange full rate motor SQ1102 single speed, pool built unknown, TF-100 Spa and Baracuda G3

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    Re: My Weekly test, Add or not add

    If pool math is telling me to do it, why shouldn't I?
    Because PoolMath can't think. Poolmath takes a point where you are and tells you how much to add to get to another point.....that's it.

    You, on the other hand, know (as a budding TFP'r) that as long as your pH is not completely out of whack (it isn't) that you would do well to simple leave TA right where it is.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: My Weekly test, Add or not add

    PoolMath is not telling you to do anything you aren't asking it to tell you to do. You put your current TA in and you left your target set to the default. PoolMath does not know you are trying to keep your TA and pH low to avoid calcium scaling. Try to think of it as a colorful calculator, it only gives you answers based on what you feed in to it.

    Richard320 is the resident expert on dealing with chronic calcium problems, follow his advice.
    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
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    Richard320's Avatar
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    Re: My Weekly test, Add or not add

    Quote Originally Posted by Chula Vista 45k View Post
    Good morning everyone. I plugged my weekly test results into pool math and it is telling me to add baking soda, 423 oz.

    CL 5-10
    PH 7.2
    FC 10 (Just added last night after heavy use over the weekend)
    CC 0
    TC 10
    CH 1000 ( I need to drain when possible)
    TA 60
    CYA 60

    I was told not to add the baking soda in another thread, but I am confused. If pool math is telling me to do it, why shouldn't I?
    Poolmath will tell you to add based on what you input as your target. It just does the math -- YOU tell it where you want your levels to be. It only makes target suggestions. You have to decide whether or not they apply to you. Poolmath is likely also suggesting you to replace all your pool water. So why aren't you? Why take poolmath's advice on TA but not CH?

    I've already made my argument why you should leave TA alone here. I was trying to keep it simple. You want the long answer? You need to keep CSI down. That's the Calcium Saturation Index. A negative number indicates that it will start leaching Calcium right out of the plaster, weakening it. A positive number indicates it will start leaving Calcium scale on the walls. Scale is like grow-your-own 320 grit sandpaper right on the wall. People will scrape knees and elbows on the wall and get roadrash.

    Go plug all your numbers into both sides of poolmath. Look at CSI.

    Then go to the target column and change things. See what happens to CSI when the pH climbs to 7.8. It will climb over time. Guaranteed. Hover the pointer over the CSI row. "Potential to become scaling." Now leave pH at 7.8 and raise TA to 80. "Scaling likely." If you'd rather go from a risk to a sure thing, raise your TA. Leave pH at 7.8 and TA at 80 and see what happens if the CH rises to 1100, which it will eventually through evaporation and refilling with your 425 CH tap water. Now go back and reduce TA to 60. CSI went from a sure thing back to likely even at high pH and higher CH. What changed? TA went from 80 to 60, that's all. So why not just leave the TA at 60?

    The higher the TA, the faster the pH will rise. The higher the TA and the higher the pH, the more likely you are to grow scale. So if you raise TA now, you'll be having to add acid again in a couple days to lower pH, which will also lower TA, so you get to buy and add both baking soda and acid and end up with a net gain of nothing....except possibly some scale on the walls, which doesn't dissolve anywhere near as fast as it can form.

    As an aside, I'll bet the refill water has higher TA than the pool. So when you top off, you'll be raising TA anyway.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Chula Vista 45k's Avatar
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    Re: My Weekly test, Add or not add

    Than k you Richard, you have provided me the explanation I was looking for. I just wanted to know why and you have answered that.
    45k, IG,Plaster, Pentair FLT FNS PLS 60 DE, A.O. Smith 1hp square flange full rate motor SQ1102 single speed, pool built unknown, TF-100 Spa and Baracuda G3

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