Why Is My Hot Tub Water Green and How to Clear It

Green water looks alarming, but it’s usually one of two things — and both are fixable.

Algae vs. metals

Algae: if the water is green and a little slimy or murky, low sanitizer let algae bloom. Metals: if the water turned green right after refilling and is still clear, dissolved copper or iron in your fill water is the culprit.

Clearing an algae bloom

1. Test and rebalance pH and alkalinity.
2. Shock the water with a strong dose of sanitizer.
3. Run the jets and filter continuously until clear.
4. Clean the filter thoroughly afterward — algae and dead organics clog it fast.

Handling metals

Use a metal sequestrant and consider a hose-bib pre-filter when refilling. If green water keeps returning despite good sanitizer, a fresh drain and refill with treated fill water usually resolves it for good.

Prefer to skip the upkeep entirely? Get a free quote from Bubble Balance — we keep hot tubs crystal-clear across Wilmington and the Cape Fear coast on a simple monthly plan. Or call (910) 264-3361.