How to Get Rid of Hot Tub Foam (and Keep It Away)
A little foam when the jets kick on is normal. A thick layer of bubbles that won't go away is not. Foam usually means something in the water is raising the surface tension: soaps, lotions, body oils or other organic buildup. The good news is it's easy to fix.
What causes hot tub foam?
- Lotions, cosmetics and hair products that wash off when you soak.
- Laundry detergent in swimsuits. Even a small amount left in the fabric can make foam.
- Body oils and sweat building up faster than your sanitizer and shock can break them down.
- A dirty filter that can't trap oils anymore, or one cleaned with household soap.
- Low calcium hardness. Very soft water tends to foam more easily.
- Old water. After a few months, dissolved buildup gets high enough that foam keeps coming back.
The quick fix: a defoamer
A defoamer such as Leisure Time Foam Down breaks up the bubbles fast. Follow the label, adding a small amount right where the foam is. It's great before guests come over, but it only treats the symptom. If you keep needing it, work through the steps below.
How to stop foam coming back
- Test the water with test strips and bring alkalinity, pH and sanitizer into range. Our test strip guide shows how to read them.
- Shock the tub to burn off the oils and organics behind the foam (how to shock a hot tub).
- Clean the filter, using a spa filter cleaner rather than household soap, and rinse it well (how to clean a hot tub filter).
- Check calcium hardness. If it's below the range your spa maker suggests (often about 150 to 250 ppm), raising it can help. See water balance products.
- Use an enzyme treatment like Leisure Time Enzyme weekly to help break down oils and lotions in the water.
- Drain and refill if the water is more than three or four months old or nothing else works. Adding a line cleaner such as Jet Clean before you drain helps clear buildup hiding in the plumbing (full drain and refill steps).
Habits that prevent foam
- Rinse off in the shower before you get in, without soap if you can.
- Rinse swimsuits in plain water instead of washing them with detergent.
- Keep hair products and lotions out of the tub where possible.
- Shock weekly and after parties, and keep the filter clean.
- Drop a few oil absorbing sponges in the skimmer to soak up oils.
Shop hot tub water care for clarifiers, enzymes and foam control.
Related reading:
Safety first: always follow the directions on the product label and your hot tub maker's manual. Add chemicals to the water one at a time, never mix chemicals together, and store them dry, cool and out of reach of kids and pets. Questions? Send us a message.
