How to Lower pH in Your Hot Tub: A Complete Guide

By Jon Filson

Hydropool Hot Tubs and Swim Spas

Published Jan 11, 2024

Once you get a hot tub, one of the first things you realize you’re in for is regular water checks.

You’re going to take test strips and dip them in your tub for a couple of seconds and check them on a regular basis, lining up the colored strips with the side of the container. At some point, your pH is going to be dark orange instead of medium and you’re going to have to get it back to balanced.

What do you do then?

We get asked by recent buyers frequently about water balancing and pH is one of the most common elements. It’s one of the most common questions we get at our Hydropool retail outlets, and that’s why we wanted to write this article, to give you the best answer we can.

So in this article, we will tell you:

  1. How to lower the pH, in the very next section, so no waiting
  2. What is pH in your water
  3. Why your pH changes
  4. How to keep your pH from swinging as much as possible
  5. Why keeping your pH balanced matters
  6. How to create a hot tub maintenance routine

Hopefully by the end you’ll have a good idea of how to keep your pH balanced, along with the rest of your hot tub.



How to Lower Your pH in Your Hot Tub Quickly

  • What you need: You need to buy a product called pH-minus. It might be called different things or spelled different ways: pH reducer or pH down are other examples.  
  • How much does it cost: Prices range from $10 to $25, depending on the size and what you get.
  • Where you can get it: You can order this product online, buy it at stores like Home Depot. Your hot tub retailer, if you bought from one, will certainly have it.
  • Are they different: They all work similarly but are not the same. They are all acids: Common choices are liquid muriatic acid or dry sodium bisulfate.
  • Our best tip: If you’re new to water balancing, we’d suggest working with your retailer at first, because they will know their product line and how it works and be able to give you good advice. If you want to branch out later and try other brands -  because you can get them cheaper or easier, because you think they will work better or whatever reason – you can do still do that.   
  • Just as important: Before you adjust pH, make sure your alkalinity is balanced. Alkalinity and pH are often linked: if alkalinity moves your pH will move afterwards. Think of alkalinity as your water’s ability to withstand change, or it’s “buffering” ability.

Adding the pH Reduction Chemicals to Your Hot Tub

  • Remember, adjust your alkalinity before you adjust your pH. Alkalinity should be between 80 and 120 ppm. If you correct the alkalinity first, the pH level will slowly adjust.
  • Following the label instructions, you will need to calculate how much pH-minus you require. You will need to calculate it based on how much water is in your hot tub and what level your pH is at.
  • Have the cover off.
  • Have the jets are running.
  • Make sure the water is warm, at least 70F.
  • A scoop should come in the container. Put the appropriate amount of pH-minus into the hot tub. You will have to do the calculations yourself here: Hot tubs vary in size.
  • Then you wait.
  • Let the pump circulate the water for two cycles. This allows any gases to dissipate into the air.
  • pH will take some time to drop. Retest the hot tub again after at least two hours. Do not use it in the meantime.
  • If the pH hasn’t adjusted, wait again, another two-three hours.
  • If the pH hasn’t adjusted by this time, repeat the process until the pH lowers to the appropriate level. The goal is to be between 7.2 and 7.8 ppm, which should put you in the “ok” range of your test strip.
  • Watch your alkalinity during this process as it will likely decrease at the same time. Remember, if it lowers, pH is soon to follow. 

What is pH in Your Water

pH measures the concentration of hydrogen ions in your water. This tells you whether your water is leaning toward being more acidic or basic.

What Happens if My pH is Out of Balance?

High pH means your water is more of a base, which will cause your sanitization to be ineffective, leading to cloudy water, itchy skin and ruined filters.  Low pH means it is more acidic, which means the water will increasingly corrode your hot tub. Both need to be addressed.

Why Your pH Changes

pH changes because alkalinity changes, is one way to look at it. This can happen due to high usage, or rainwater coming into your hot tub or if you add water to your hot tub due to evaporation. While pH levels are one of the more consistent aspects of your hot tub water, it’s one of the most important ones to look after.

How Often Should I Check the pH in My Hot Tub Water?

You should check it at least once a week when you do your regular hot tub maintenance. If your hot tub is being used heavily, such as every day, you will want to check it more frequently to keep an eye on it. You don’t need to become obsessive: Some people check their water too much and start chasing it. Water’s properties will fluctuate: the main thing is to keep them in a good range.  

How to Keep Your pH From Swinging as Much as Possible

pH changes the most when the alkalinity isn’t balanced. If it’s out of balance, then pH can swing. That’s why it’s important to set your alkalinity before setting your pH and keep on eye on it. The good news is that once you establish pH (and alkalinity) they are likely to remain relatively constant unless you make a change – like adding water to your hot tub or using it much more than usual.

How to Create a Hot Tub Maintenance Routine

The easiest method to maintaining a hot tub is to check it once a week and balance the water then. Clean your filter once a week and once every few months, soak your filter in a cleaning solution.

You can also check your water if you have changed your schedule or how you have used your hot tub. Major uses may require an extra shock treatment.

What is Actually Happening to the Water When You Lower Your pH?

Science time! When the acid is introduced to the water, it increases the hydrogen concentration and lowers the pH as a result. The acid also reacts with existing bicarbonate in the water which is what reduces the alkalinity.

How Do I Lower pH in a Hot Tub?

We get asked about water balancing all the time at Hydropool, and about pH specifically. Making sure your water is balanced is key for anyone with a hot tub. Otherwise, you won’t have a good experience and your hot tub won’t last as long.

Since we want everyone to enjoy their hot tub, we put together this guide on lowering pH. We hope it helped you. If it didn’t, we still want to help! Please reach out the local Hydropool dealer closest to you. You can find retailers here

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