Hot Tub Water Care: What Is Alkalinity?

A common question that we hear from hot tub owners who are trying to balance their water is “What is Alkalinity?” which is often followed by “How do I keep it at the right level?” This blog will explain what water alkalinity is, why it is important to keep it balanced and how to make adjustments to it.

What Is Alkalinity?

Total alkalinity is the measure of your hot tub water’s ability to neutralize acids. It’s an important part of balancing pH levels and is sometimes referred to as “buffer” because it helps the water resist drastic changes in pH.

For those of you that own a Sundance Spa from The Sundance Spa Store, Total Alkalinity is the third square down from the top on your 6-in-1 Test Strip. The ideal range for Total Alkalinity is between 80-120 ppm (Parts Per Million).

Why Does It Matter?

Unbalanced alkaline levels can have an adverse effect on your hot tub water’s appearance (giving the water a green tinge) and in some cases can have a drying effect on your skin.

Low alkalinity is the more serious of the two extremes. It can cause green water and rapid fluctuations in pH, because the water can’t as easily counteract the effects of acids, such as acid rain or naturally occurring minerals.

If Low alkalinity levels are left unchecked for a long period of time, they can have a negative impact on the surface of your hot tub and can also cause corrosion of your hot tubs internal equipment.

An alkalinity level that is too high can also result in green water, as it reduces the effectiveness of of the sanitizer that you add to your water (Sun-Boom), which performs at it’s best in well balanced water. While low alkalinity can cause erratic pH, high alkalinity typically causes really high pH levels.

High pH levels in your hot tub water can result in a calcium build up, which can make the water cloudy and cause scale to form (as you might see inside your kettle). Calcium can cause yellowish flakes to appear in your hot tub water and can have a negative impact on your spa’s jet performance and equipment if not dealt with.

If you are having issues with calcium build up, a deep cleanse of your hot tub’s plumbing can help. We recommend the use of Whirlpool Rinse or Spa Marvel Cleanser to break down calcium build up in your spa’s plumbing, and regular use of Prevent II to help prevent a build-up of calcium. Come in and see us for more information.

How Do You Balance Alkalinity?

Total alkalinity should be kept at 80–120 ppm. To raise low alkalinity and stabilize your pH, use Alka-Plus. One capful of Alka-Plus usually increases the alkalinity level one square on your test strip.

It is best if you increase your alkalinity gradually over a period of time rather than adding a large amount of chemicals at once. Make an adjustment, and then do another test the following day to see if you need to add anymore products to the water.

To lower high alkalinity, use pH Reducer. As a rule of thumb, one capful of pH Reducer will bring your Alkalinity level down about 1 square on your test strip. pH Reducer should be added gradually to ensure you do not add to much chemical and bring the levels down too low.

As pH reducer brings down both alkalinity and pH, you will need to test your pH level the day after making an alkalinity adjustment to see if you need to increase your pH level to the acceptable range. Always get your Alkalinity level in to the acceptable range before adjusting the pH.

If you still have a green tinge to your water after the alkalinity has been adjusted, check the sanitizer level is where it should be (add 30 grams,1 Capful of Sun-Boom if required).

If the sanitizer level is good, then add 100 grams (4 capfuls) of Spa Shock to restore water clarity.

Whenever you add chemicals to your hot tub water, you should turn on one of your jet pumps to circulate the water for 20 minutes.

After adding chemicals, keep your spa cover open to allow your hot tub water to breathe and to release any chemical odors in to the air to both protect your spa cover and ensure no chemical smell builds up under your cover.

Monitoring alkalinity in the water is an important part of balancing your hot tub water and will help keep your water clean and clear for longer periods of time and increase the effectiveness of your spa sanitizer.

You can always bring a water sample in to any of our 6 locations (Burlington, Hamilton, Mississauga, Oakville, St. Catharines & Vaughan) and we can test it for you and advise you on how to balance your water and keep it looking and feeling amazing!