Signs Your Spa Is Over- or Under-Chlorinated

Maintaining the perfect balance of chlorine in your spa is vital for safety, hygiene, and enjoyment. Excessive chlorine can irritate the skin and eyes, while insufficient chlorine can lead to bacterial buildup and cloudy water. How can you tell if your spa’s chlorine levels are off? Here are some key signs that your spa is over- or under-chlorinated, along with steps you can take to address the issue.  

Skin and Eye Irritation

One of the clearest signs of over-chlorination is irritation. If your skin or eyes feel dry, itchy, or inflamed during or after a soak, the chlorine levels might be too high. While chlorine is necessary for sanitation, too much of it strips natural oils from the skin and disrupts the eye’s moisture barrier.

By contrast, if you notice redness, itchiness, or minor rashes developing a few hours after using the spa—especially in the armpits or swimsuit area—low chlorine could be the cause. Insufficient sanitization allows bacteria to thrive, which can trigger skin sensitivities and infections.

Unpleasant Odors

A strong, chemical smell suggests an imbalance in chlorine levels. Ironically, a powerful chlorine odor usually indicates that there is not enough free chlorine and too many chloramines—compounds formed when chlorine combines with contaminants like sweat or body oils. This typically means your spa is under-chlorinated and unable to oxidize these compounds.

Freshly chlorinated water should have a faint, clean scent. If your nose wrinkles every time you lift the spa cover, it’s time to test the water and take corrective action.

Cloudy or Foamy Water

Balanced water should look crystal clear. If your spa appears cloudy or has a foamy surface, it’s another indication that something is wrong. Low chlorine levels allow organic matter to accumulate, resulting in cloudy or murky water. Foaming can also occur when the sanitizer is too weak to break down soaps, oils, or leftover detergents from swimwear.

Over-chlorination can also cause cloudiness, especially if the pH and alkalinity levels are off. High chlorine levels can precipitate calcium out of solution, creating tiny particles that cloud the water.

Fading Swimsuits and Spa Surfaces

High chlorine levels not only affect people but also damage materials. If your swimsuits are fading or the spa’s plastic or rubber components are cracking or discoloring, excessive chlorine could be the cause. Chlorine acts as a bleaching agent and can degrade surfaces and fabrics over time. To prevent this, check your chlorine levels regularly and rinse off before and after every soak.

Maintaining Proper Chlorine Levels

If you want to maintain a safe spa, test your water at least twice a week and adjust chlorine levels as needed. The ideal range for chlorine in a hot tub is typically between one and three parts per million (ppm). Automated chlorinators, floating dispensers, or spa shock treatments can help maintain balance. If you’re unsure about your water levels, consult Atlantic Spas and Billiards, a spa supply store, for water testing kits or expert advice.

Knowing the signs your spa is over- or under-chlorinated helps you stay ahead of maintenance issues and enjoy your hot tub.