The Perfect Pool Blog

Alkalinity and Your Pool

If you’re a pool owner, testing and balancing your pool's water is already a regular part of your maintenance routine. Whether you handle it yourself or hire a pool professional, and whether you're a new pool owner or have owned your pool for many years, some aspects of pool water chemistry may still be a bit of a mystery—and alkalinity may be one of the most mysterious elements.

A Word About Water Balance

When we talk about "balancing"; pool water, it involves a few key factors—primarily pH, Total Alkalinity and Calcium Hardness, in conjunction with your pool’s water temperature. Properly balanced water allows your sanitizer to do its job and work effectively. It keeps your pool clear, healthy and safe for swimmers and protects your pool and its equipment from scale, corrosion and other hazards. Pool professionals refer to the Langelier Saturation Index (LSI or SI) to help ensure that pool water is not corrosive or scale-forming.

Alkalinity FAQs

Understanding alkalinity and its role in water balance will help you get the most enjoyment out of your pool by keeping it safe, healthy and looking nice for years to come. Here are answers to some of the frequently asked questions about alkalinity in pool water.

1. What is Total Alkalinity?

The alkalinity level of your pool is measured as Total Alkalinity (TA) and refers to the total number of alkaline particles found in your pool’s water. Alkaline particles are defined as those whose pH is higher than 7.0. Total Alkalinity is measured in parts per million (ppm). If you can keep your pool water’s alkalinity level in the ideal range (80 to 120 ppm), your pH is more likely to remain within its proper range as well.

2. What role does alkalinity play in your pool’s water balance?

Keeping Total Alkalinity in the ideal range protects your pool by helping the pH level of your water remain stable. Maintaining a proper pH level is essential to protect your pool’s equipment and interior surface from damage. Keeping your pool’s pH in the neutral range allows your sanitizer to do its job effectively so that swimmers don’t have to experience the red, burning eyes and itchy, irritated skin that can occur when pool water isn’t properly balanced.

It’s also important to note that alkalinity is one of the best indicators of your pool’s overall condition. If your alkalinity level is in the normal range, it’s a very good sign that your pool water is healthy and safe.

3. How are alkalinity and pH related?

We can’t talk about alkalinity without also discussing pH and how the two are related.

Since alkalinity’s primary purpose in your pool is to help the pH remain stable and resist changes, some experts define alkalinity as a “buffer”, or a “guard” and some use the analogy of a “roof” or an “umbrella” to describe how alkalinity protects your pool’s pH level and keeps it within range. No matter how you refer to it, alkalinity works hand in hand with pH; you must maintain both to achieve and sustain clean, clear, healthy pool water.

4. What can affect the alkalinity level in your pool?

The main factors that affect your pool’s alkalinity level are the same ones that impact your pool’s pH. The primary culprits are swimmer waste, rain, leaves and other debris. Your area’s water supply could also tend to be naturally high or low in alkalinity. Since these things are all a regular part of everyday life and out of our control, your pool water needs to be tested and balanced on a regular basis.

5. What are the ideal ranges for alkalinity and pH in your pool water?

The ideal range for your pool’s Total Alkalinity level is between 80 and 120 ppm. pH is measured between 0 and 14 with 7 considered “neutral”. You want your pH level to be stay between 7.2 and 7.6. Keeping your alkalinity in the ideal range is the best way to maintain a neutral pH.

Pool water with high alkalinity and pH is referred to as “basic”. When your pool’s alkalinity and pH are too low, the water is “acidic”. Both conditions can cause swimmer discomfort and be damaging to your pool.

6. What happens if your pool’s alkalinity level is too high?

Having basic water means the alkalinity level is too high and your pH will most likely be high as well. Basic water can become cloudy and cause your pool’s sanitizer to lose its effectiveness which leads to skin and eye irritation for swimmers. That’s also when chalky white scale can form in your pool. Scale is most noticeable on your pool tile around the waterline and under spa spillovers, waterfalls and other water features. Unsightly scale can be difficult and expensive to remove.

7. What happens if your pool’s alkalinity level is too low?

If your pool’s alkalinity level is too low, your water will be acidic. In acidic water, pH becomes unstable, causing it to bounce up and down making it difficult to achieve proper balance. Like basic water, acidic water can also lead to skin irritation and eye irritation for swimmers. If left unchecked, acidic water can eventually cause corrosion and damage to both your pool equipment and your pool’s interior surface.

Gunite pools and pools with decorative interior finishes like pebble, quartz and glass bead finishes are at high risk for corrosion, deterioration and discoloration due to unbalanced water; they will eventually require refinishing. In some cases, improper water chemistry can void a pool finish’s warranty. Fiberglass pools risk etching and corrosion of the gel coat and vinyl liners can also become discolored or deteriorate more quickly if water remains out of balance for too long.

Testing and Balancing

Clearly, keeping your pool’s water properly balanced with alkalinity in the proper range and pH neutral and stable is essential to having a healthy, safe pool where swimmers feel comfortable and to prolong the life of your pool’s surface and equipment for years to come.

Fortunately, testing for Total Alkalinity is simple and there are a number of easy options available in the form of test strips or drop tests (also known as reagents).

In addition, you may want to consider adding a Chemical Analyzer that works with your automation system to allow you to check pool chemistry levels remotely. For salt chlorinated pools, a Chemical Controller is also available to help keep your water continually balanced. Talk to your local pool professional about the best options for testing and balancing your pool.