From cloudy water to heater issues, real hot tub owner stories meet the science that explains what happened and how to fix it.
Every hot tub owner has “that story.” A green spa before a party. Jets that sputter mid-winter. Let’s walk through common questions with the real-life situations behind them — and the science that explains what’s going on.
Story 1: The Green Party Spa
Question: “Why did my water turn green overnight?”
Science: Metals in fill water oxidized when chlorine was added. That reaction turns water green.
Fix: Add a metal sequestrant and filter continuously until clear.
Story 2: The Cold Soak
Question: “Why won’t my hot tub heat past 90°F?”
Science: A failing heater element or clogged circulation filter reduces heat transfer.
Fix: Clean the filter, check flow, and test the element.
Story 3: The Bubble Surprise
Question: “Why did foam appear after I hosted friends?”
Science: Body oils, lotions, and detergents create surfactants that trap air into foam.
Fix: Shock, rinse filters, and plan a partial drain if it persists.
Story 4: The Midnight Noise
Question: “Why does my spa hum even when not in use?”
Science: Pumps on circulation cycles are designed to run. Placement near bedrooms amplifies noise.
Fix: Adjust cycles or relocate the spa if possible.
See more answers in Tub Time and fast fixes in Quick Fixes. For safety and health info, visit the CDC Healthy Swimming page.
FAQ
Why is biofilm dangerous
It protects bacteria from sanitizer, making water unsafe. A line purge removes it.
Should I drain after heavy use
If water turns cloudy or foamy quickly, a drain and refill is the fastest reset.