While you may enjoy a bubblebath in a regular tub, foam is a problem when it appears in a hot tub. While bubbles are perfectly normal, foam is not. Many companies manufacturer commercial de-foaming products that can be added to the water, but if you prefer a more natural and cost-effective solution, there are a few household products that you can use on your hot tub.
Vinegar works as a powerful de-foaming agent. If you have only a thin layer of foam in the hot tub, you can pour vinegar straight into the water. This should be done at a ratio of 10 to 1. For example, if the hot tub holds 100 gallons of water, use 1 gallon of vinegar. The downside is you may notice a slight hint of a vinegar smell to the water, but this will evaporate over time.
Vinegar and Baking Soda
Mix a solution of vinegar and baking soda in a bucket, with one 1 part baking soda, two parts vinegar and nine parts water. Although this combination will create an initial foam, the vinegar will help activate the baking soda. Pour the solution into the spa and let it work for at least 30 minutes. The solution will dissolve the skin particles and oils that are causing the foam.
Draining the Spa
If you've tried both methods and the spa is still full of foam, the best solution is to drain the spa, clean it thoroughly and refill it with fresh water. At this time you can add a chlorine shock treatment to reduce the chance of having foam occur. In some cases, household products simply won't be strong enough to get rid of the foam and you'll have to revert to a chemical to solve the problem.
Always shower before getting into a hot tub. Don't use any soap or shampoo products, just rinse yourself off in warm water. This will remove skin oils and flakes that can contribute to foamy water in a hot tub. Ask your guests to do the same and ensure that no one wears any type of body lotion into the tub. Cleaning the tub regularly will also help reduce the occurrence of foam.