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How to Fix a Green, Brown, or Purple Pool

Think of the perfect pool. What does the water look like in your ideal pool? We’d wage that it probably looks clear with a sparkling blue tint.

Pool owners know that their pool’s water can sometimes have an unexpected tint – a murky grey-brown, a cloudy green, or even a surprising purple!

Why do pools have slight variations in water colour – and when is the colour of your pool a cause for concern? Read below to learn about the factors that combine to create your pool’s unique appearance, and which colours you should be concerned about.

READ MORE: Saltwater vs Chlorine Pools

Why Does Pool Water Colour Vary?

Your eyes aren’t playing tricks on you – the water colour really does differ from pool to pool. The difference in colour will depend on a few factors:

Water Balance

Pool water contains a few chemical differentiations, most notably, pH level. This is a number that should be balanced using chemicals, ideally reaching 7 on the pH scale of numbers 1-14. If the pH level is too low, the water is considered acidic. If the pH level is too high, it is considered alkaline. Both of these instances can lead to discolouration, among other problems.

Size and Depth

The deeper your pool is, the stronger or more saturated the colour will be. If you think the colour of your pool’s water is too strong, it’s possible that the depth simply makes it appear that way.


It’s entirely possible that the colour you perceive from your pool can actually be explained by the reflection of the sun. It might look brighter or darker based on the sunshine (or lack of) or air quality in your region.

Your Type of Pool Liner

The pool liner is the layer of material on the floor and walls of your pool. Some liner types pick up dirt and grime easier, or get scratched away more easily, compromising the appearance of your pool’s water.

READ MORE: When to Replace Your Vinyl Pool Liner

Discolouration and What It Means

Brown Water

Brown water is particularly unappealing for a pool – but what does it actually mean? Likely, your water turned brown due to a water quality issue.

Brown might indicate that you have a lot of iron or other metals in your pool. If this occurs, continue to test the pH level of your pool, and adjust accordingly. Most likely, you’ll need to bring your pH level higher, as you probably have an alkalinity problem.

Otherwise, your pool may be collecting dirt and other pollutants. Make sure you regularly vacuum and clean your pool.

Green Water

Green pool water is fairly common for pool owners. In most cases, it indicates that you have algae buildup in your pool.

The term ‘algae’ can refer to plenty of organisms that appear in aquatic environments. They can grow quite rapidly – especially during extreme heat. That’s why many pool owners feel blindsided to have a clean pool one day and a green, algae-filled pool the next.

Chlorine is one of the most effective ways to eliminate algae, which is why it’s important to regularly check on your algae levels. You can also find products that specifically target algae in climates like yours.

Protecting your pool with a cover is another effective way to keep pests out of your pool.

Cloudy Water

What should you do if your pool’s water is cloudy or hard to see through? You may choose a number of strategies to restore your water’s clear, crisp appearance. Potential problems include:

  • Not enough chlorine – In this case, your pool water may also have a green tint, indicating an algae buildup. To solve this issue, simply continue to increase the amount of chlorine in your pool.
  • Chemical imbalance – To solve this issue, try to balance your pH and TA levels, and continue to monitor them
  • Dirt buildup – To solve this issue, vacuum your pool regularly, also ensuring that your filters are clear of dirt and dust.

Black or Purple

You probably wouldn’t expect an indigo-tinted shade to appear in your pool’s water – so how could this happen?

The purple shade is most likely from an issue involving your water’s chemistry. Specifically, this is called copper cyanurate. When this occurs, it means that you have too much copper and cyanuric acid in the water.

Alternatively, it’s possible that you have too much chlorine, or that dark algae has made itself at home in your pool.

Either way, you can solve the problem by carefully monitoring how many chemicals you are putting in your pool. Additionally, consider checking your pool’s filtration system.

The Takeaway

Most pool owners agree that clear, sparkling blue water is the most desirable look to have. Unfortunately, issues like chemical imbalances and pests can leave pools with less desirable shades.

At Poolamara, we have decades of expertise on any and all pool issues. Contact us today with your pool repair-related questions, and we’ll set you on the right track to enjoy your pool in its best form.