Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 2 of 2

Thread: Alkalinity and Borax

  1. Back To Top    #1

    Alkalinity and Borax

    I'm working on lowering my TA in order to add Borax to my water. It was quite high at 130. I added acid and it is now down to 90. I'm aerating it right now and plan to add more muriatic acid to continue to lower it. How low should I take it in order to be able to add the Borax and not raise the TA too much. I'd like to keep it on the low side since the TA of my refill water is very high.


    27' above ground
    17,100 gallons
    sand filter

  2. Back To Top    #2

    Join Date
    Mar 2007
    San Rafael, CA USA

    Re: Alkalinity and Borax

    Borax is optional and not at all necessary. If the reason you are lowering your TA and want to add borax is because you tend to have the pH rise, then lowering the TA to around 70 ppm is usually enough, but it really depends on your pool. I suggest you try a certain TA level and see where the pH wants to settle. If it is reasonably stable at 80 ppm, leave it there; if it still tends to rise, you can lower it. If it's more stable at 70 ppm or even 60 ppm, then make that your target. After you've found a reasonably stable point, then adding Borax will reduce the frequency of acid additions, though not necessarily the total amount of acid needed over time.

    Note that if you have a plaster pool you may want to compensate for the low TA by targeting a somewhat higher pH (say 7.7 or 7.8) and/or increasing your Calcium Hardness (CH) level to have the Calcite Saturation Index (CSI) closer to 0 to protect plaster surfaces. For vinyl, the CH doesn't matter (well, you don't want it high since you don't want scaling, but low is fine).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts