Confused about pool alkalinity? We’ve got the answers! Alkalinity helps to keep the water chemistry balanced, which helps keep your pool healthy (and safe to swim in) as a whole.

Pool alkalinity is one of the most important pool chemical criteria to pay attention to in order to keep your pool safe. 

A major part of being a responsible pool owner is making sure that the water chemistry is balanced properly. If you’ve had a pool for a while, you know just how delicate that chemistry can be. And if you’re a novice, now is the best time to learn how to balance your water the right way. 

Your pool’s water chemistry is created by adding specific amounts of certain chemicals, and alkalinity is directly correlated to maintaining the pH. 

Proper pH is key to safe and clean water. In this article, you’ll discover how pool alkalinity plays a role. Learn what it is, what can happen if it becomes unbalanced, how to adjust it, and why it’s so important for the overall health of your swimming pool!

What is Pool Alkalinity?

Pool alkalinity, sometimes called total alkalinity (TA) works to keep the pH of your pool balanced. It helps to prevent sudden changes and acts as a “cushion” in order to maintain the pH levels where they should be. 

If you allow your pool alkalinity to go down, the pH levels will rise or fall at a rapid rate, which is known as pH bounce. If you add pH balance chemicals before you adjust the alkalinity, the pH will become very unstable, which makes maintaining consistent chlorine levels difficult. What’s more, when the alkalinity levels in your pool get too high, you’ll have a hard time adjusting the pH which could result in a pH lock.

The ideal range for pool alkalinity is between 80 ppm and 120 ppm and the acceptable range is between 60 ppm and 180 ppm. You can measure yours with a swimming pool test kit.

What Can Happen if Your Pool Alkalinity Is Too High or Too Low

Remember, it’s important to keep your pool alkalinity balanced — not too low and not too high. Common causes for unbalanced alkalinity include:

• Heavy rains
• Sunscreen
• Oils from the body
• Pool shock
• Water source with naturally high alkalinity

If you let your alkalinity levels rise above 180 ppm, you’ll cause a pH lock. The surface of your pool’s walls and floor could become rough to the touch, and your filters and heater may clog up. You’ll also experience cloudy pool water because the water won’t be able to circulate properly.

When you allow the alkalinity levels to drop below 60 ppm, you’ll cause a pH bounce. This can cause your pool to become stained, and it will irritate your eyes and skin. It will also encourage fluctuating pH levels and has the potential to break your pool heater.

How to Adjust Pool Alkalinity

If you do end up with too-high or too-low pool alkalinity, there are easy ways to fix it. 

If you need to raise the TA, use sodium bicarbonate. Also known as baking soda, you can find large bags of sodium bicarbonate at your local pool supply store or even at the supermarket. You should use it if your TA goes below 60 ppm.

If you need to lower the TA, you can either introduce more water or use a pool-safe acid. The acid will lower the alkalinity as well as the pH and bring things back down to the acceptable range of 180 ppm.

When you’ve finished adjusting your pool alkalinity, make sure to test the water to determine whether the levels are where they should be!

The Bottom Line

No matter which way you look at it, proper pool alkalinity keeps your pool safe and enjoyable to swim in. When you let it slip, you’ll end up with itchy skin, a stained pool, cloudy water, clogged filters, and damaged equipment. As you can see, pool alkalinity is of utmost importance when it comes to maintaining your pool. Don’t underestimate it!