How To Increase Alkalinity In A Hot Tub

Learning how to raise alkalinity in a hot tub is vital to your hot tub. Low alkalinity in a hot tub is not good as it can lead to various maintenance issues that will cost you more money. So, it is important to increase the alkalinity of your spa when it’s low. As hot tub owners, this post will guide us on why we need to test our spas and raise the alkalinity in a hot tub when it’s low and lower it when it’s high.

The alkalinity in a hot tub is increased by adding baking soda or alkalinity increaser to the hot tub water. Balancing pH is different from balancing alkalinity. The pH of your spa water may be balanced but still has an issue with alkalinity. Increasing the alkalinity in the hot tub as you will learn here, isn’t just about making your hot tub less acidic. You need to raise the total concentration of alkaloids that are found in the water.

To enjoy the Total Alkalinity (TA) in your hot tub, you need to have the right concentration of alkaloids. The benefit of this is that when you raise or have a higher concentration of alkaloids, the hot tub’s pH would be stable. This is what your hot tub needs.

The alkaloids referred to here are bicarbonates, hydroxides, carbonates, and other minor alkaloids. They are alkaline substances that buffer the pH of the water, therefore, neutralizing acids.

What is Alkalinity?

We usually mistake alkalinity to be pH, but they are different things that serve different purposes. Unlike pH which is the measurement of how basic or acidic the hot tub water is, alkalinity is the measurement of water’s ability to resist acidification.

So, alkalinity can simply be described as the measurement of the water’s capacity to withstand the change in pH. Here, you will learn the easy step-by-step guide on how to increase alkalinity in a hot tub.

Why do you need to increase the alkalinity in your hot tub?

Having low alkalinity is bad for your hot tubs. Starting from your hot tub’s components, low alkalinity is bad for it.

This may cause the surface of the shell to become pitted i.e. having an indentation or being hollow on the surface. It can be etched as well. It also affects the protecting layer of the shell and makes it peel.

Again, with low alkalinity in your hot tub, any part that was made of metal and comes in contact with this water will immediately wear away. With an issue like this, you will be risking your heaters, pipes, and even your heating elements.

In the long run, calcium scaling might take place, which would become very difficult to keep the plumbing free of scale buildups. It also makes it difficult to keep the surfaces of your hot tub clean.

Increasing the alkalinity in your hot tub until it becomes well balanced is important for creating a healthy and safe hot tub environment. You don’t need to continue using a hot tub that its an alkalinity is low. This will be irritating to the eyes, skin, and even throat. Moreover, it can lead to a cloudy hot tub.

To avoid all of these, you need to test your hot tub to know its alkalinity. If the test shows any indication that you need to raise the alkalinity, then it is pertinent you go for it. It doesn’t take much from you. Below are the different ways you can achieve this without much stress.

How to raise alkalinity in a hot tub

There are two main ways by which you can increase alkalinity in a hot tub; by using alkalinity increaser products or baking soda (sodium bicarbonate)

The use of Alkalinity Increaser products

There are assortments of alkalinity increaser products. But it is always advisable to buy alkalinity increaser products that are made from sodium bicarbonate. The reason is simple; sodium bicarbonate is the primary substance that aid in boosting water pH.

If you are looking for products that can increase the alkalinity of your hot tub, then you can try products like SpaBoss Alka-Rise, Alka-Plus, and Leisure Time Alkalinity Increaser:

SpaBoss Alka-Rise

This is a product created by CAPO Industries. It’s one product that can increase or boost the alkalinity levels in your hot tub. It is cost-effective. The major ingredient of this product is sodium bicarbonate which is 100% effective.

It is simple to use – just add the product to some water, depending on your alkalinity reading, to increase it. You wouldn’t regret using this product as it is perfect for keeping the chemical levels in your hot tub quite right. Moreover, it makes the hot tub water clear, clean, and safe for use


This is another chemical product that can be used to increase alkalinity in a hot tub. It is known to be an alkalinity booster and its major ingredient is sodium hydroxide. So you can go ahead to use this product as it has met the USDA requirements. Also, it has been approved for use to prevent iron oxide deposits, mineral deposits, and dissolved oxygen. So you can go ahead to add it to your water.

Leisure Time

Leisure Time Alkalinity Increaser is a good product that you can use to increase the alkalinity of your hot tub. You can use it with any sanitizer. It helps to prevent pH bounce and gradual water balancing. I recommend using this product when the alkalinity tests are below 80ppm (parts per million).

To use this product is simple; you only need to add 1oz to your hot tub, and then allow the water to circulate for about 30 minutes. You can then retest the water with your test strip. Repeat the process until you reach the desired level which is between 80-120ppm. However, I recommend you aim between 100 – 120ppm.

Why use alkalinity increaser products

  • They help to balance the water pH level.
  • These products help to eradicate corrosion of metal parts, damaging or staining of the surfaces.
  • They help to prevent pH fluctuations that might have damaged your hot tub’s moving parts.
  • With alkalinity increaser products, the hot tub’s jets, pumps, and plumbing will be intact.
  • They prevent the wearing out of metallic materials.

Increasing the alkalinity of a hot tub with baking soda

Will baking soda raise alkalinity in hot tub?

If you don’t want alkalinity increaser products, you can simply use baking soda. This is one of the chemical substances that quickly increase alkalinity in a hot tub. The good thing about baking soda is that it is readily available and it is very cheap too. You can just pick one from the retail store nearest to you.

How to increase Total Alkalinity (TA) with baking soda

Below are the procedures for the use of baking soda in increasing the alkalinity of the hot tub.

Things needed

You need to have the following handy:

  • Measuring spoons
  • Baking soda
  • Water test strips

Steps to effectively use baking soda to increase the alkalinity of your hot tub

  • First, go through the hot tub manual or read the tag to know the water’s holding capacity
  • Then, test the hot tub’s Total Alkalinity (TA): This test will help you to know if you need to increase the alkalinity of your hot tub or not. To achieve this, you would need to turn off the hot tub jets. Then determine the alkalinity by the use of a test strip

How much baking soda does it take to raise alkalinity in a hot tub?

This is why you should know your water’s holding capacity. You need to add a tablespoon of sodium bicarbonate to your hot tub for every 100 gallons of water it is holding. So, if the hot tub holds about 500 gallons of water, you will add 5 tablespoons of baking soda.

Next, turn on the hot tub jets while allowing the water to circulate the baking soda for about 2-4 hours. You can at this point retest the alkalinity level of the water. If the alkalinity level is still low, put off the hot tub jets and add more baking soda to your water.

You can continue to alternate this by circulating, and then adding more baking soda until you get to the accepted range which is between 100ppm – 120ppm.

Why use baking soda to increase alkalinity

  • It never causes severe burns to the skin unlike some alkalinity increaser products
  • It does not leak to damaged areas they are stored in
  • It has no adverse effects like harsh chemicals that are used for increasing the alkalinity of the hot tub

Moreover, draining and refilling your hot tub at intervals will aid you in increasing the alkalinity of your hot tub without needing to add any additives to your water.

What’s needed to be adjusted first in the water of your hot tub: Alkalinity or pH?

The first thing that needs to be adjusted is the alkalinity of your hot tub, so you can be able to get the proper pH range. The importance of doing this first is that it will aid in buffering the pH: it simply means it will help to prevent pH fluctuations.

To check the level of alkalinity in your hot tub to enable you to adjust it properly, you need to use fresh and high-quality test strips. Don’t let your hot tub have excess bromine or chlorine levels. High levels of chlorine or bromine can give you false alkalinity and pH readings which hampers proper adjustment of the alkalinity.

Importance of increasing the alkalinity in your hot tub

Both low calcium hardness and low pH levels can cause huge damage to the hot tub; the same applies to having a low alkalinity level. In reality, this low-level might not be easily noticeable on the surface of the hot tub equipment. But, it will have a significant effect on the pH level of the hot tub because it will drive it way too low.

Of course, the resultant effect increased the acidity of the water. And with water of this nature, it will be bad for the skin and might cause an irritated eye or itchy dry skin. Hence, you need to keep the alkalinity in your hot tub safe and balanced so that you can enjoy the following:

  • There will be no cracking, pitting, or etching on surfaces.
  • No issue of wearing out of the hot tub.
  • You wouldn’t have the issues of stained hot tub walls.
  • You would enjoy seeing your surfaces very smooth without issues of corrosion of any metal surfaces.
  • The pump seals, heating elements, pipes, and gas fire heaters in or around the hot tub would be in a better shape.
  • With the balanced alkalinity level of your hot tub, you will need fewer hot tub sanitizers, since the alkalinity will be more effective for hot tub usage.
  • There will be less pH bounce; this means that you will not be experiencing quick fluctuation of pH level.


The need to increase the alkalinity of your hot tub can’t be overemphasized, because its importance is enormous. You wouldn’t only protect your health, but also, the health of your hot tub equipment. You should always have the basic tips on how to raise your alkalinity at your fingertips.

Always, you should first find out how large your hot tub is ( i.e the gallons of water it holds) and have your target range at heart. Though the standard range is between 80-120ppm, we recommend that you go for 100 – 120ppm.

Take note of this: don’t forget to allow your hot tub for about 12 -24 hours after raising its alkalinity before using it.

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