Can Too Much Chlorine or Bromine Damage a Hot Tub?

Many spa owners believe that if a little sanitizer is good, then more must be better. While chlorine and bromine do an excellent job keeping water clean and sanitized, excessive sanitizer levels can actually be harmful to the spa over time.

From our experience servicing hot tubs throughout the San Fernando Valley and Los Angeles County, we have seen cases where prolonged exposure to high sanitizer levels has contributed to premature wear and damage to spa components.

What Can Excessive Sanitizer Damage?

When sanitizer levels remain too high for extended periods, it can begin affecting various components throughout the spa, including:

• Heater elements
• Stainless steel heater manifolds
• Pump seals
• Jet components
• Pillows and headrests
• Spa covers
• Gaskets and O-rings
• Plastic fittings and plumbing components

In many cases, the first signs of excessive sanitizer levels are fading, discoloration, cracking, or deterioration of pillows, covers, and plastic components.

Why Does This Happen?

The simple way we explain it to our customers is that both chlorine and bromine are sodium-based sanitizers. Chlorine is commonly added as sodium dichlor or trichlor, while bromine is commonly added as sodium bromide.

Since sodium is a form of salt, every time sanitizer is added to the water, the sodium content continues to increase. While sanitizer is necessary to keep the water clean and safe, excessive amounts over long periods can eventually contribute to water that becomes increasingly harsh on spa components.

From our experience, once sanitizer levels remain excessively high for extended periods, the water can become increasingly aggressive toward the materials used throughout the spa. Over time, this may contribute to corrosion of metal components and deterioration of plastics, rubber seals, pillows, covers, and other spa parts.

This is why we recommend maintaining sanitizer within the recommended range rather than continually adding more chemicals in an attempt to correct aging water.

More Chemicals Is Not Always the Answer

One of the most common mistakes we see is customers continually adding more chlorine or bromine when the water quality starts declining.

In many situations, the problem is not a lack of sanitizer at all. Instead, the water may simply be old and overloaded with contaminants, dissolved solids, and spent chemicals.

When this happens, adding more chemicals often provides little benefit and can sometimes make the situation worse.

In many cases, customers are trying to correct old water by adding more sanitizer, when the better solution is often a drain and refill.

Our Recommendation

If you find yourself constantly adding sanitizer to maintain water quality, it may be time to evaluate the overall condition of the water. In many cases, the problem is not a lack of sanitizer, but simply old water that has reached the end of its useful life.

This is one of the reasons we recommend draining and refilling your spa every 6 months. Fresh water gives you a clean starting point and allows your chemicals to work more effectively without continually adding sanitizer to aging water.

If you would like to learn more about why we recommend draining and refilling your spa every 6 months, be sure to read our article:

"How Often Should a Hot Tub Spa Be Serviced?"

If you need help or are unsure where to start with your water chemistry, feel free to download our quick water care guides. We offer guides for both chlorine and bromine spas to help simplify routine maintenance and water balancing.

As always, if you have any questions, please don't hesitate to reach out. We're always happy to help.