How to Lower your Total Alkalinity

Today, let’s discuss how to lower your Total Alkalinity in your Hot Tub or Swim Spa. Sometimes, especially as a new Hot Tub or Swim Spa owner, balancing your water can seem to be a challenging endeavor. I hope the following information will help you.

What is Total Alkalinity? Simply put, it is a measurement of the waters ability to neutralize acidity. Many people also refer to Alkalinity as a “buffer”. Alkalinity is the ability of the water to keep the elements less acidic by maintaining the right pH level.

Why do we need to care if our water has high alkalinity? High alkalinity causes green water, as it will reduce the effect of sanitizers such as chlorine or bromine. High alkalinity also causes high pH levels. High pH results in an increase of calcium, which will make your water cloudy and cause scale to form on the surfaces of the tub. Over time, this can harm the jets and filters in your hot tub or swim spa.

What should be balanced first is a common question? pH or alkalinity? My suggestion is to always balance your alkalinity first as it tends to be the easiest to manage. Before doing anything with your water, you first need to determine what your TA (Total Alkalinity) is in your water. You can either use a test strip, a titration kit or bring in a water sample to your hot tub or pool store. Titration kits are the most effective for at home testing. If you use city water, many cities, and municipalities often publish the quality of your water online which will include your alkalinity. So, if you are filling directly from your garden spigot this is another way. Essentially, before you do anything with your water, you need to know where it is at to begin with.

For our purposes today, we are going to assume that your TA is high. We now know, we need to lower it. You have two options. You can use a liquid acid such as Muriatic Acid or you can use a Sodium Bisulfate. Either will work. Once you determine which product to use, now you need to do a little math. Find out how many gallons are in your tub or swim spa. You will already know your TA based on testing. If your TA is at 170 and you want to bring that down to 110 you will need to lower your TA by 60 PPM. Most of the instructions you will find will show you the measurements to lower your TA by 10 PPM at a time. Here is where some of that math comes in. You want to lower your TA by 60 PPM so simply multiply the amount needed to lower your TA by 10 PPM by six. Once you have added the required amount of acid, run your jets for 20 to 30 minutes. Then, simply let the tub sit for an hour without the cover on to let to breathe. Test again and determine where you are at with your TA. If you are in normal range, my suggestion is to then cover the tub and let it sit for 24 hours. Then test again. If you are still in the proper range, we can move on to the next step in balancing your water.

One thing to always remember when balancing your water. Take your time and have patience. Balancing should take a day or two to get it right. By doing the proper steps at the beginning, you will save yourself time and effort weeks later.

If you have any additional questions, please do not hesitate to reach out to us at Ahh-some Watercare. We are here to help you with all of your water needs.

4 Comments. Leave new

  • I I’ve been trying for weeks to get my alkalinity down. I even drained the hot tub cleaned it and refilled it. And I still have high alkalinity In the meantime I’m adding the pH decrease or cuz that’s what everybody says to do. And all it’s doing is lowered my pH to bottom levels. Then my bromine was low because the alkalinity was high so I added some bromine now my bromine is too high My alkalinity is too high My pH is low and my calcium hardness is low. And I’m at my freaking wit’s end because nothing is working to lower the alkalinity. I have been trying this for weeks now with the drain and now at another week. Can someone please tell me what to do because I am lost and I’m frustrated. Cuz I’d really like to use my hot tub cuz my back is killing me and in the last month I’ve been unable to do that with all this work and all this money spent on chemicals I’m about to be out of another round of PhD creaser and have to go buy more and I don’t understand I’ve even used muriatic acid nothing is lowering the alkalinity it’s through the roof

    • Hi Kris. We are just following up to see how your tub is doing. I know you and Jim spoke a few weeks ago, so we just wanted to check in. Thank you.


  • Avatar photo
    Parag Agarwal
    January 26, 2024 9:15 am

    Hi my water source has TA of 417. How can I lower it down to 80-120 ???

    • Good morning. In order to lower your TA, you need to use Muriatic Acid or pH Decreaser. Follow the instructions on the back of your pH Decreaser, but based on a 400 gallon tub, you will probably need at least 6 oz. of decreaser to start moving it down and then test periodically after that. What are you using to test your water? Feel free to email me at [email protected]
      Jim Parker


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