Is Epsom Salt Harmful to a Hot Tub?

Problems

• Salt water can corrode metal faster than plain water, no matter what type of salt is used. If a hot tub’s shell, pipes or any parts are made of metal, then Epsom salts should not be used. Hot tubs are drained every 1 to 4 months, unlike a conventional tub which is drained immediately after a person finishes a bath. The longer Epsom salts and water stay in contact with metal, the faster that metal will corrode. But if the hot tub and pipes are made of PVC piping, Epsom salts or other mineral salts can be used.

Expert Advice

• Some brands of hot tubs such as Whirlpool strongly advise customers to drain and clean the hot tub after every 10th bath with Epsom salts, sea salt or any other mineral salts. Run hot water for ten minutes to thoroughly flush out the pipes. Epsom salts in a fine grain or a powder dissolve completely in water and work better in hot tubs as opposed to coarse grains.

Warnings

• Using Epsom salts or any other type of salt in a hot tub may void any manufacturer’s warranty. Some lines of tubs may approve some brands of salts specially made for that tub. Never assume that Epsom salts are an acceptable alternative for the mineral salt brand that the manufacturer specifies in its warranty. What brand of Epsom salts to use does not matter. All brands of Epsom salts contain identical contents, notes the Epsom Salt Council.

Alternative

• Epsom salts provide magnesium and sulfate that can be safely absorbed through the skin. Epsom salts can be safely used in a conventional bathtub. Although the water will not swirl like in a hot tub, one can still soak in still hot water and Epsom salts without harm to the conventional tub. Drain and rinse the tub immediately after the bath. Never use a hot tub if pregnant.