Soaking in a spa isn't so relaxing when the spa is plagued by thick, unsightly surface foam--not the scented, fluffy type that comes from bubble bath. To combat this unhealthy foam buildup, spa owners often resort to store-bought defoamer or an anti-foaming agent. While these chemical additives reduce and hinder the formation of foam, you can use natural, simple and cheaper alternatives.
Treat the undesirable spa foam with a chlorine shock treatment. Though your homemade defoamer will break down the foam, it won't completely eliminate the particles that created the foam in the first place. For optimal results, use a chlorine shock treatment such as Nava Quick to treat the root cause and ensure your homemade defoamer works to its best ability.
Turn on your spa and add 1 part distilled white vinegar to every 10 parts water. For example, if the spa capacity is 100 gallons, add 1 gallon of white vinegar.
Alternately, add 1 part baking soda, 2 parts white vinegar and 9 parts water to create an added defoamer. The acidity of the vinegar and the alkalinity of the baking soda will react to create superfine bubbles, producing a light, fluffy candy-textured substance that will dissolve unhealthy particles creating the foam in the first place.
Drain and completely empty the existing water in your spa and replace it with new, fresh water. This should be done regularly to maintain healthy water, even if no foam is in your spa. It's the best way to eliminate foam and alleviate health concerns.