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How to Convert a Bromine Spa to Saltwater

Caryn Anderson

Using salt to sanitize spa water is an appealing alternative to traditional bromine sanitizing. Saltwater has enhanced soothing and healing elements. It also has a natural ability to sanitize spa water while reducing the need to use defoamers and other spa additives.

Saltwater systems allow you to keep spas sanitized with fewer chemicals.

Salt softens the water, minimizes scaling and scum at the water line, and simplifies maintenance.

  1. Select a saltwater generator. There are a wide variety of options available, ranging from simple plug-in generators that can be plugged into the existing filtration system, to systems that must be installed in the spa's cabinet and as part of the spa's plumbing. Additionally, saltwater systems differ in the type of salt used. Table salt (sodium chloride) can be used to generate chlorine for sanitizing your spa. You can also choose a bromine-generating saltwater system that uses sodium bromine, a relative of table salt, to sanitize water with natural bromine. Saltwater systems convert sodium to chlorine or bromine by passing it through an electrode cell placed within the hot tub's water circulating system.

  2. Empty and thoroughly clean the spa to remove any residue or scum. This is particularly crucial if you are switching to a saltwater system that generates chlorine, since bromine and chlorine should not be combined.

  3. Install the saltwater system in your spa according to the manufacturer’s instructions. Plug-in systems are the easiest to get up and running. If the system requires any plumbing modifications, consult a plumber or spa professional to ensure correct installation.

  4. Fill the spa with fresh water and the amount of sodium bromine recommended by the manufacturer. As the water circulates, bromine generates from the salt, sanitizing the spa. Generators convert sodium bromine to bromine for a short period of time before the bromine recycles itself back to sodium bromine. As a result, you will need to add salt only occasionally, such as if there is a large amount of water splash-out or when changing the spa water.

  5. Check spa water weekly to ensure that the bromine levels are optimal for sanitation. White vinegar lowers alkalinity and water pH when used as a ratio of 3 to 6 ounces for every 100 gallons. Raise total alkalinity with baking soda, using a ratio of 1 to 3 tablespoons per 100 gallons.

  6. Tip

    Salt can be more corrosive than standard spa chemicals. Periodically inspect the filter and spa shell for any signs of scaling or staining.


    Check your spa’s warranty before converting. Converting your bromine spa into a saltwater system may void the factory warranty that accompanies the spa when you purchase it.

    Consult a spa professional before installing any system that requires plumbing modification to avoid damaging your spa's plumbing system.