How to Balance my Hot Tub pH and Alkalinity?

We want you to ensure relaxing and enjoying your hot tub all year round so we’ve made a short tutorial special for you on how to balance your hot tub pH level and total alkalinity.

You might remember acids and bases from high school chemistry. When a solution (that’s a chemical mixed with water) contains extra hydrogen ions, it’s acidic. When the solution has fewer hydrogen ions than plain water, it’s basic.

Total alkalinity is important because it keeps the pH level stable in your hot tub. Total alkalinity is important to your spa water because it is often the first level that you adjust before you add your other chemicals. Think of total alkalinity as the "gatekeeper" of hot tub water chemistry.

Your total alkalinity range will need to be between 125 parts per million and 150 parts per million. To adjust alkalinity levels, you'll need to add an alkalinity increaser or decreaser slowly to your water.


1. Test alkalinity.

To test your hot tub’s alkalinity, dip test strips in the water. Test strips will provide a quick and accurate reading of the pH level, total alkalinity and sanitiser levels in the water, allowing you to make the appropriate chemical adjustments if required.

It is important to test the hot tub water on a regular basis to ensure it is clean, safe and healthy for bathers. When using the test strips, make sure to follow the instructions on the bottle carefully to ensure you get the most accurate reading.


2. What pH level should your hot tub be?

On the general pH scale, seven is perfectly neutral water. Lower numbers are more acidic, and higher numbers are more basic.

When you test your hot tub water with test strips or a liquid test kit, they’ll show how acidic or basic your hot tub water is. Ideally, pH levels in your spa should measure between 7.4 and 7.6.

If your spa’s pH measures outside that range, you could be in for some unhealthy and potentially damaging water symptoms in your spa.


3. Low pH in Your Hot Tub

Any pH level below 7.4 could spell trouble. The lower the pH level, the more acidic your hot tub water is. Highly acidic water makes it more difficult for your sanitizer to work effectively, leaving bathers in your hot tub exposed to potentially harmful contaminants.

This increases your chances of being exposed to bacteria, such as pseudomonas aeruginosa (the cause of hot tub folliculitis) or legionella (which causes Legionnaires’ Disease), among others. Low pH in your hot tub may also cause corrosion in spa components, which can be expensive to replace.


4. High pH in Your Hot Tub

When your pH levels climb beyond 7.6, your spa water can be described as basic. What this means for you is poorly sanitized water, carrying the same risks as any other cause of ineffective sanitizing.

Basic spa water is also prone to forming scale and drinking pumpkin spice lattes year-round. Kidding—it’s not that kind of basic. But it really will cause flaky scale to build up on your spa surfaces.

The scale is due in part to high calcium hardness caused by the high pH. Cloudy water is another symptom of a high pH level in your spa.


5. Raising Your Hot Tub pH

If you have acidic water, you will need to increase your pH. Ask your pool store professional for a pH increaser or a product with active sodium bicarbonate. No, we are not talking about baking soda! Although the names are similar, they are slightly different compounds so please do not start pouring baking soda into your hot tub! Trust the professional products with this one.

Please be mindful that your pH increaser will also raise the total alkalinity. Make sure that after adding and circulating the increaser, that you once again test for pH and total alkalinity.

Increaser products typically have an "ashy" compound and may cloud your hot tub water. For this, we recommend adding a clarifier to your spa water to bring your water back to that clear, shiny look.


6. Lowering Your Hot Tub pH

 If you have basic or alkaline water, you will need to lower your pH. Ask your pool store professional for a pH decreaser or a product with sodium bisulfate; which is the main ingredient used for lowering pH.

Pay attention to the instructions on your pH decreaser. Some products require you to dilute the product before adding it. You'll also need to circulate your spa water after adding in your decreaser to allow the product to infiltrate the body of water entirely. Be sure to also check your total alkalinity as a pH decreaser can influence your total alkalinity level.

Please make sure when you test your re-test your pH after treating your water, that you also test the total alkalinity level!


If you have any other questions about pool and spa products please do let us know - we are here to help! 

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