Why is my spa water green? (Common causes and how to fix)

Green water in your spa indicate that something is not right. This article addresses the causes of green water and the steps to restore crystal clear water in your spa!

Maintaining crystal clear water in your spa is important because it not only looks more inviting, it usually indicates that your water is balanced and safe for you to bathe in.

A greenish colour in your water can indicate insufficient sanitiser, low pH, algae, high metal content or residue from beauty products like fake tan.

Read on to find out what the cause may be in your spa and how to restore sparkling clean spa water!

This article covers:

What causes green spa water?

Your spa water can begin to take on a greenish tinge when something is not right with the balance of your spa water. Here are some of the common causes of green water in your spa or hot tub.

Green-tinted spa water caused by low pH levels

The pH level in your spa should be between 7.2 and 7.8. If your pH level is lower than 7.2, it is too acidic, which can mean your sanitiser won’t work properly and you may experience skin and eye irritation.

In addition, acidic water can begin to eat the components of your spa - even start dissolving things like your copper heater element - increasing the metal content in your spa water. More about that later.

How do I fix the pH in my spa?

To determine if your pH levels are within the correct range, use test strips or a digital tester to check your water pH is within the range of 7.2 to 7.8.

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Can a green tint be caused by insufficient sanitiser?

It is important to always follow the recommended dosage on your sanitiser labels. The APVMA (Australian Pesticides and Veterinary Medicines Authority) recommends a daily dose of 6-10g of chlorine per 1,000L of water in your spa.

We understand that sometimes your spa maintenance can get neglected for a period of time - life happens! Even if your spa is not in use, it is important to keep maintaining the daily dose of sanitiser to ensure that bacteria don’t have a chance to form in your spa water. (Trust us - 2mins a day of sanitising will save you 2 hours or more later!)

If you’ve fallen behind on your sanitising routine, don’t despair, you can add a shock dose or a dedicated spa shock product to get your water back under control. Read on below for details on how to shock your spa.

Can Insufficient filtration / circulation cause a green tint in my spa water?

Another possible cause of green water in your spa is insufficient filtration. By default, your spa should arrive with the daily filtration cycle set, but it may need adjusting depending on your bather load or other factors.

Also, sometimes kids can play with your settings and you may need to check that something hasn’t been fiddled with!

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How long should I run my spa filter each day?

A portable spa should filter for 8 hours every day (8/24 hrs). A swim spa should filter for 16 hours per day (16/24 hrs)

If you need to, you can add an extra hour of filtration each day to help restore your spa water.

Also, make sure your date and time are set correctly on your spa controller so the filtration will run at the correct times.

Locate your spa controller manual and find the section on adjusting filtration.

Note: If you have a Fisher® or Vortex® spa, you will most likely have a SpaNet® controller.

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Is the green tint in my spa caused by algae growth?

If you notice the formation of green slime, then you have algae beginning to form in your spa. Excessive phosphates in your spa water provide food for algae to feed on.

How do I stop algae in my spa?

To stop and remove algae in your spa, use a spa shock treatment in your water to help kill off the algae growth. If the algae persist, use a dedicated algaecide to treat the algae growth.

In the worst-case scenario, you may need to run a pipe cleaner/degreaser through your spa plumbing, empty your spa completely and start again with fresh water.

Can I use Fake Tanning and other beauty products in my spa?

Fake tanning products are a definite no-no in your spa! They will react with your sanitiser and leave a green or brown residue on the surfaces in your spa, and can upset the balance of your water also.

What does high Metal content in my spa water do?

Green-tinted spa water can also be caused by extra metal content in your water. Water from wells or bores can contain metal content like copper or iron which can react with your sanitising or shock chemicals causing the green tint to appear in your water.

Is it safe to get into a spa with green water?

A very light tint of green is usually still safe to get into, but it’s an early indication that there is a problem with your spa water.

If you act quickly as soon as you notice the change in colour, you may be able to treat the problem and restore your water to its former clear state without the need to drain your water and start again. Read on to find out what steps you can take to clear up green spa water.

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How to treat green spa water

If the green-tinted spa water has only just appeared in the last 24 hours, you may be able to clear it up quickly and easily.

Remove your cover, pillows and headrests and add a shock dose of your sanitiser. (Approx 60g per 1,500L of water). Or you can use a dedicated spa shock product. Be sure to check the dosage on the label of your spa sanitiser or spa shock and follow the instructions carefully.

Keep the cover off and turn on your spa jets for one cycle to ensure the treatment is circulated evenly throughout your spa water.

Leave the spa for a few hours then check back to see if the water has begun to clear and the green tinge has disappeared. Once your water has cleared up and the sanitiser has had a chance to gas off your water, you can use the spa again!

If your water has been green for more than 24 hours, and the steps above have not been successful, then you will need to drain the water.

Run a pipe cleaner/degreaser through your spa plumbing before you empty, to ensure all build-up of oils and grime are loosened and will be flushed out when you drain your spa. When your spa is empty, take the opportunity to thoroughly wipe down the interior of your spa and clean your filters.

Refill with fresh water and re-balance and sanitise your spa water.

Will shock clear a green spa pool?

Yes, In some cases, spa shock can help clear out the green tint in your spa water and restore it to crystal clear. Spa shock reacts with organic contaminants that can build up in your spa water - oxidising them so your spa water can return to normal.

Read more about spa shock, the different types of shock available and how to use it.

What causes cloudy spa water?

Now that we’ve covered the main causes of green spa water, we’ll address one of the other common spa water quality issues - cloudy water.

Cloudy water can be caused by a pH level that is too high, high alkalinity, not enough sanitiser, external substances and products introduced into your spa, and old water that simply needs to be changed.

Read the detailed guide that explains why spa water gets cloudy and how to fix it.


Steps to keep your spa water crystal clear

Follow the steps below to maintain your spa and keep the water sparkling and beautiful!

  • Cover your spa
  • Shower before entering the spa
  • Use a vacuum or skimmer to remove debris
  • Keep up with water testing and balancing
  • Add sanitiser daily to your spa
  • Check your circulation and filtration
  • Clean and change filters
  • Relax and enjoy your crystal clear spa water!

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Got more questions?

Talk to us or email us your spa questions and we'll be happy to help!

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