How To Solve Green Hot Tub Water

by Steve

This article will help to troubleshoot your green hot tub water problems. There could be algae growing or maybe even the metals such as copper and iron lurking within!

green hot tub spa water

Algae in Spa Water

If your hot tub water is green and also slightly cloudy it could be an algae problem. Algae breeds well in warm water but can be easily prevented by the correct use of hot tub sanitizers. It’s also important to keep the tub covered as much as possible because algae need daylight to grow.

Deep Clean and Flush

If you suspect algae and haven’t changed the water for a while, ie. over a month, then I’d suggest that you drain the tub and do some deep cleaning and flushing. Try using an algae treatment such as SeaKlear Yellow Klear Algae Treatment Solution. It’s for pools so you should only need a small amount!

Then you could use SeaKlear Spa System Flush, to remove any slimy gunk Biofilm & algae from your spa/hot tub hoses. Run the jets for an hour or so and then leave the water sitting overnight before another flush, drain and refill.

Test, Shock & Balance

It’s important to test the new water and take note of the chemical composition for starters. Next you’ll need to adjust Total Alkalinity and pH and then apply a strong dose of chemical shock either chlorine or bromine as is your preference.

To get a basic balance you can use TA Increase to raise and Alkalinity Down to lower alkalinity.

To adjust the pH you could use pH reducer. Alternatively raise pH with pH Up.

Allow the hot tub to run for a couple of hours and then to stand overnight with the shock chemicals working on the algae. This should kill off any remaining micro-organisms. The next day, bring the hot tub up to temperature, do some further testing and get the Total Alkalinity adjusted  between 80 and 150 ppm and then the pH at 7.2-7.8  . Keeping within these parameters will ensure the efficient use of your sanitizer and you should now be free of algae and green spa water.

Metals Causing Green Hot Tub Water

Is your problem is clear green water?  This may not be caused by algae but could be due to an excessive content of copper or iron. I’ve not personally come across this problem but it could be down to the minerals already in the water that you’re using to fill your tub.

Copper in Salt Spa Water

A clear green tint in spa water could be a sign of copper.  It has good anti-bacterial properties, is not harmful to you and is one of the ingredients used in some mineral sticks.  Copper can have a strong reaction to the bromine used in salt water spa treatments and many of the metal removing chemicals can’t actually remove copper from water.

How To Remove Metals

Spa water chemicals like Spa Metal Gon “Tie Up” (sequester) the traces of iron, copper, and other metal buildups in the spa water. Metal removers can stop staining on the surfaces and waterline of your hot tub and also hopefully prevent the green spa water.

The following metal sequestering agents are designed to remove metals from spa water:


Leisure Time D Spa Metal Gon

SeaKlear Spa Natural Clarifier

Pool Mate 1 pt. Minquest Metal Free


 

My Case Scenario

During the hot summer months I tend to drop my hot tub temperature down by a few degrees from 38C to 36C. This is mainly because the kids often use it and the slightly cooler water is more comfortable for them.

Our’s is a bromine system which we’ve found is much kinder to our skin and eyes than chlorine. After a couple of weeks the Alkalinity starts to drop and there are signs of green water.

I solve this by raising the temperature to 38C for a few days to stop the algae growing and also add  TA Increase in small doses to bring the alkalinity back up.

After a day or so the TA rises and with a little help from a bromine top up and pH UP if needed, the green water dissappears and we’re back on track.

Check my review of the best selling hot tub chemicals to find more about spa water care treatments.


Spa & Hot Tub Owners Blog .com

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