What Causes Alkalinity To Drop In A Hot Tub?


There are a few reasons that can cause alkalinity to drop in a hot tub, including: 

  • Adding too much chlorine, which can lower the pH and alkalinity levels. 
  • Not circulating the water regularly enough, allows algae and other contaminants to grow and throws off the pH balance. 
  • Using too much pH decrease or acidic cleaner in the hot tub can also lower the alkalinity levels. 

If you find that your alkalinity levels have dropped, you’ll want to raise them back up as soon as possible.

The best way to do this is by using an alkalinity increase, which you can get at most pool/spa stores. 

Why Does My Alkalinity Keep Dropping?

One of the main reasons why alkalinity levels in a pool can drop is due to evaporation.

When water evaporates, it leaves behind salt, minerals, and other chemicals that can lower the pH and alkalinity of the water.

Another reason why the alkalinity level might drop is because of too much rain or runoff.

This can also lead to higher levels of chloride in the pool, which can also lower hot tub’s alkalinity level.

If you think that either of these might be causing your alkalinity problems, it’s important to take steps to raise the levels back up.

This can usually be done by adding baking soda or another chemical solution to the water.

Can You Go In A Hot Tub With Low Alkalinity?

If you have low or high alkalinity in your hot tub, it’s not advisable to go in.

The reason for this is that low alkalinity can lead to increased levels of chlorine demand and it can also make the water more susceptible to the pH levels and fluctuations.

This means that you could end up in a setting where the pH is too high or low, which could be irritating or even dangerous.

It’s always best to err on the side of caution when it comes to hot tubs and spa pools, so if you’re unsure about the level of alkalinity in your hot tub water care well, it’s best to consult with a professional or test the water yourself before getting in.

How Do I Fix Low Alkalinity In My Hot Tub?

Low alkalinity in your hot tub can be caused by a number of things, such as using too much chlorine, acidic water, or high levels of bather load.

If the alkalinity in a hot tub is low, you can raise it by adding baking soda to the water.

Baking soda is a natural alkaline and it will help to balance the hot tub’s pH level and increase the alkalinity of your hot tub water.

Does Baking Soda Raise The Alkalinity Hot Tub?

It depends on what you mean by baking soda.

Sodium bicarbonate is a chemical that is used as a leavening agent in baking and it can also be used as an antacid to relieve heartburn, sour stomach, and indigestion.

When it comes to hot tubs, some people use sodium bicarbonate as a clarifier to remove calcium carbonate and magnesium hydroxide scales from the water.

These deposits can make the water cloudy and affect the pH of the water.

By adding sodium bicarbonate to the water, raises the total alkalinity amount of the water and helps to clear away these scale deposits.


  • Jason

    Jason is an experienced writer, having contributed to many popular websites over the years. He currently writes for Big Hot Tub, a blog about everything hot tubs. When he's not writing or working on his blog, Jason enjoys spending time with his wife and two young children.