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Do You Know What Causes Foam In A Hot Tub?
- Oct 30, 2018 -

Maybe you have seen sea foam for yourself. Maybe you have heard about it in fairy tales (The Little Mermaid, anyone?) or seen it in movies. Sea foam is fundamentally the same as hot tub foam, just with a slightly different chemical makeup.

For foam to appear, it needs three things: water, air, and surfactants. If you’re not a chemistry geek, surfactants are basically super-sticky molecules that reduce the surface tension of a liquid, which makes it easier for substances like oil and water to mix.

Whether it is in the Pacific Ocean or your spa, water isn’t just good ol’ H2O. Sure, it might look crystal clear, but it is actually stuffed with dissolved salts, proteins, detergents, and other organic compounds—many of which are surfactants.

So your spa contains water and some surfactants, even if you properly maintain your chemistry. But if you slip a little on your maintenance schedule or don’t clear the water after a big hot tub party, you might flip on your jets—unlocking that final ingredient—and find yourself with a foamy mess.

The actual process for forming bubbles is funny. Surfactants, while different from each other in many aspects, all have one end that is attracted to water and one end that is hydrophobic, meaning it is not attracted to water.

When you add air to the mix, the surfactant molecules organize themselves right on the boundary between air and water.