Why Is My Hot Tub Green? 2 Reasons Why

After a long, hard day, you're looking forward to soaking in your hot tub. The only problem is that when you lift the lid, you're greeted by a shock of green—not exactly what you want to see when all you want to do is relax. If you're wondering "why is my hot tub green," it's usually due to either too much algae or too many minerals. Here's how to deal with it.

1. Out-of-Control Algae

You and your family aren't the only ones who enjoy the warm water of your hot tub. According to the U.S. Department of Energy, algae—a group of organisms that can be part of the bacteria, chromista, plant, or protista kingdoms—love warm water. 

The microorganisms also tend to thrive in still water with a pH over 7.2. So if it's been a minute since you last soaked in or sanitized your hot tub, you may find that algae have taken over. 

How to Fix It

If algae are turning your hot tub green, you need to give it a shock by killing the hot tub bacteria and restoring the pH of the hot tub water. Shocking your hot tub increases the chlorine or bromine level in the tub, killing off the algae. Follow the instructions on the shock treatment to ensure you do it correctly. After shocking the tub, remove and clean the filters to get rid of any traces of algae.

Depending on how much algae you're dealing with, a shock treatment may be sufficient to restore the water's blue color. But, when the tub is completely overrun by algae, they may stick around even after treatment. In that case, you'll want to drain the tub and clean the hot tub interior, using a non-abrasive household cleaner or a product specially made for cleaning hot tubs. 

Refill the tub, and add the appropriate treatment to maintain adequate chlorine or bromine levels. Test the water after 24 hours to make sure the pH and chemical levels remain in range.

To keep the algae under control, keep up a regular schedule of shocking the tub and also running it, so that you get the water churning.

2. High Mineral Content

Certain types of minerals, notably copper and iron, can give your hot tub water a greenish tinge. Metal or mineral content may be to blame if you're keeping up with hot tub maintenance and maintaining appropriate treatment levels but still seeing green water. 

You can easily tell if the tub is green due to algae or minerals by touching the water or sides of the tub. Algae typically makes the water or tub sides feel slimy to the touch. 

How to Fix It

To get the green out, you'll need to do something about the mineral content. One option is to change the source of your hot tub water, which may be particularly useful if you're filling the tub with well water.

The other option is to treat the water to neutralize the minerals. Consider installing a pre-filter to trap heavy metals and keep your water clear.

When to Call a Pro

If you're not sure whether algae or minerals are to blame for your hot tub's green color or you're not comfortable giving your tub a shock treatment on your own, it's worthwhile to hire a local hot tub repair pro to diagnose the problem and treat it. 

When hiring someone to fix your hot tub, it's usually best to find a technician who works with your specific brand. Your best bet may be to contact the dealer that sold you the hot tub and ask about repairs. To help keep the green from returning, you may also want to find out if the dealer offers maintenance plans. 

How to Prevent Green Hot Tub Water

A little bit of maintenance can go a long way toward keeping your hot tub clean and clear:

• Test the water's pH and chemical balance at least twice a week.

• Sanitize or shock the hot tub once a week. 

• Run the hot tub frequently to keep the water moving.

• Inspect the tub's filters every other week.

• Clean the tub's filters once a month.