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Thread: Alkalinty and pH in new salt water pool??

  1. Back To Top    #1

    Join Date
    Jul 2008
    Sinking Spring, PA

    Alkalinty and pH in new salt water pool??

    My pool is 5 days old. It was filled with spring water from a local water company.

    The alkalinity started off at 200. I have been adding muriatic acid and dry acid and right now it is at 150. My pH is at 6.8 and my FC is at 4.0. My CYA is 50. From reading the info in Pool School, I know it is recommended that I keep the alkalinity at 60-90 and pH at 7.5 -7.6.

    Here is my question: Since my pH is low should I raise the pH first and then lower the alkalinity or focus on the alkalinity first?

    One other question: My pool water is very clear and feels great on the skin. The water is so clear you can see to the bottom in the 8 1/2 foot deep end with no problem. However, at night when I turn on the pool lights (SAM lights set to blue) I see little floaty things in front of the light and on top of the water in the shallow end. You cannot see these in the day light and you can only see them for about two feet near the light. They are very small with a few a little larger (say half the size of a dime). The larger ones look like small pieces of tissue paper. Any idea what these are and of they are normal?

    4th Year Pool owner in Sinking Spring PA
    46'x23' Free Form Concrete (34,000 gallons), Aqua Blue Pebble Sheen Finish, Pentair IntelliChlor SWG
    Pentair Intelliflo Variable Speed Pump, Pentair D.E. FNS Filter, Pentair MasterTemp heater.

  2. Back To Top    #2

    Re: Alkalinty and pH in new salt water pool??

    first I would raise the CYA to 80 ppm. this will help in the long run with pH control.
    If the pH IS 6.8 and you are trying to lower TA then you want to raise the pH by aeration.
    These threads will be of value to you. Please read them and they will tell you what you need to do. The last one is a lot of chemistry but if you want to understand the "why" it is worth reading.


    If you have any questions after reading them please post them.

    The floaty things you see with the light at night are probably calcium from the new plaster.

  3. Back To Top    #3
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Alkalinty and pH in new salt water pool??

    If you have a fresh plaster/pebble surface, I believe you said it was brand new, you should expect the PH, TA, and CH levels to go up quickly for the first three or four weeks, and more slowly after that for up to a year.

    With fresh plaster, it is best to focus on keeping the PH between 7.2 and 7.8 and not worry about the exact TA or CH levels until the initial three or four weeks are over. All of the levels will be changing rapidly, and the PH is by far the most important one to keep control over. After things settle down, you can work on getting everything else in line.
    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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