Testing your water is only the first step—you’ll also have to balance it, depending on what needs adjusting. If you want to continue enjoying a clear, clean, and comfortable swimming pool, you need to know how to balance pool water.
By balancing your pool correctly, you can prevent pool corrosion, avoid skin and eye irritation, and protect valuable pool equipment from damage. To chemically balance your swimming pool water, follow these eight steps:
Step One: Adjust Alkalinity
A pool with low alkalinity has high acidity. If your swimming pool has alkaline levels below 80 ppm, it’s at risk of corrosion and damage — and worse, it’s unsafe for swimming. Fortunately, you can correct this problem by raising the alkalinity until it measures between 80 and 150 ppm, though some experts recommend a range of 80 to 120 ppm. To increase your swimming pool’s alkalinity, simply add the recommended amount of diluted sodium bicarbonate (baking soda). To lower the alkalinity, add dry or muriatic acid.
Step Two: Adjust pH Levels
If the pH levels are too low, the lining of your pool can become damaged, brittle, or stained. On the other hand, pH levels that are too high can cause cloudy water — and painful skin rashes. To avoid these issues, you need to balance your pool’s pH levels. You can raise your pool’s pH level by adding soda ash to the water. To lower your pool’s pH level, carefully add dry or muriatic acid while wearing protective gear over your eyes and hands. The best pH level for a pool ranges from 7.4 to 7.6.
Step Three: Balance Calcium Hardness
Most experts recommend using a calcium hardness increaser, such as calcium chloride, if your water’s calcium hardness levels fall below 200 or 150 ppm. If calcium hardness levels exceed 400 ppm, you can solve the problem by partially or completely draining and refilling the water. Anywhere from 200 ppm to 300 ppm is a good range to aim for.
Step Four: Sanitize
You can sanitize pool water with chlorine tablets, liquid or powdered chlorine, or even a salt chlorine generator. If the contamination is severe, you may need to shock the pool, which we’ll describe a little later. Ultimately, you are aiming for chlorine levels of 1 to 3 ppm, per current CDC recommendations.
Step Five: Measure Cyanuric Acid (CYA) Levels
CYA is a stabilizer that gets added to certain pool shocking chemicals, such as di-chlor. Its purpose is to prevent ultraviolet (UV) rays from burning off free chlorine, making sanitization more efficient — especially on hot, sunny days. The ideal CYA measurement for your swimming pool is between 35 and 60 ppm, unless you have a saltwater pool. In that case, aim for 60 to 80 ppm.
Step Six: Measure Dissolved Solids
Total dissolved solids, or TDS, measures how many solids (such as grime, salt, or algaecide) have dissolved in your pool water. Most experts recommend keeping your TDS levels below 1,500 ppm, or even below 1,200 ppm. If the TDS level is too high, you will need to fully or partially drain and replace the water.
Step Seven: Shock The Pool
Shocking your pool significantly increases the amount of free chlorine that’s available to destroy bacteria, algae, and chloramines. A weekly or biweekly shock helps to keep the water sanitized. Again, the optimal level of free chlorine is 1 to 3 ppm.