The Complete Guide on Hot Tub Alkalinity

What is total alkalinity?

Total alkalinity or TA is water’s ability to neutralize acidic changes in pH. It determines how much acid can be added to a body of water before a significant change in pH occurs.

In other words, it helps determine what treatment is best to keep your spa water clean and clear, rather than green-ish with goopy growth along the sides of the shell. It’s also a key offender when you check your water and it smells funny.

Why is it important to understand the functions of alkalinity?

When it comes to hot tub water chemistry, it’s important to understand these terms:

Alkalinity: The capacity of water to resist acids.
Acidity: a solution, or water mixed with a chemical.
PH: The level of acid or base in your hot tub water.

Several side effects can happen if any of these things are unbalanced, such as rapid changes in pH, skin irritation or dryness, water that has a green hue, a funky smell that is similar to mold, and if the problem goes untreated for long enough, corrosion of your hot tub shell and other components and potential failure.

Keep in mind that anything that touches or interacts with your hot tub water will affect the pH levels, which can change the chemical makeup. Think body oils, lotions, detergents (even those used to wash your swimwear), shampoos, perfumes, hair products… all the products we humans tend to use daily. Other culprits can be your local water source, or the addition of too many spa chemicals (which is not unusual). Ultimately, your goal should be to keep your water’s pH levels neutral.

How to test alkalinity levels in a hot tub

To test the alkalinity level of your spa water, begin with using a testing strip.

Dip the testing strip in the water and then shake off any excess water before comparing the color on the strip to the bottle chart on the back of the kit. The color your strip ends up with will determine your next course of action.

We recommend turning a jet on low to help circulate the chemicals into the water, and then leave the cover open enough so the water can breathe.

As you add ANY chemicals to your spa water, it’s best to allow the water to circulate for a few hours (or overnight) before re-testing, to make sure your levels are accurate.

At any given time, your hot tub water should hover between 80 ppm and 120 ppm.

How to lower hot tub alkalinity?

If your alkalinity is too high, it could be an issue of hard water in your area. The high alkalinity levels can cause the chlorine or bromine-based disinfectants to be ineffective. If your disinfectant isn’t fully functioning, your spa is at risk for mineral buildup, cloudy water, skin/eye irritation, algae formation, and scales along the surface of your shell.

Contact your dealer to discuss ways to deal with significantly hard water.

How to increase hot tub alkalinity

If your alkalinity is too low, use Total Alkalinity Increaser, following the directions lined out on the bottle. This should bring your alkalinity level up to a more neutral level.

If tests and treatments don’t take care of the issue, it’s time to try testing pH levels to find out how acidic or basic your water is. PH levels are not quite the same as alkalinity, but the testing process is similar, and the outcome will be the same when treated correctly and with the right chemicals.

It’s sometimes necessary to use shock treatment, or—in some cases—it might be time to drain your hot tub and refill it with fresh water, then add in your chemical treatments from the beginning.

No matter which direction you end up going, treating your current water, or starting over with fresh, we’re here to help you figure this out.

Originally posted on January 14th, 2022 on the Bullfrog Spas Blog by the Bullfrog Spas Brand team