How To Remove Copper Stains

Copper Stains in Pool - How To Remove Them?

Being a pool owner is tough. Before today, you probably didn't even realise that it was possible to get copper stains in your pool. Well, if you've noticed a dark tinge on your pool surface, this could be the case.

Copper stains are a fairly common problem to find especially as it is an active ingredient in many pool care products. Thankfully, it’s an issue that is just as easy to fix as it is to occur. So how do you remove copper stains from your pool?

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What causes copper stains to appear?

You may think that copper is an odd product to find staining your pool but that’s far from the case. Copper compounds, such as copper sulphate, are quite common bases for algaecides and cleaning agents.

What this means is that there is a possibility that small levels of copper deposits can be left behind if products aren’t mixed properly into the water.

Alongside that, copper deposits may also appear if your pool is supported by old copper plumbing systems or other set-ups that could contaminate the water.

From here, it only takes a few days for copper staining to become visible and indicate that there might be an issue with the quality of the pool water.

Diagnosing copper staining

When it comes to confirming that the stains are from copper, there are a few things that you can try.

Common Symptoms

First of all, confirm that the stains follow the typical pattern of copper staining:

  • Blue, teal or brown streaks
  • Unbalanced pH or alkalinity levels in the water
  • Low chlorine levels

Test Copper Level

You can purchase copper test strips to determine how much copper is present in your water.

These strips are actually designed for use with copper ionisation pools, where the owners are actually trying to keep up a certain concentration of copper, but they may be useful for this purpose too. They are inexpensive and will give you a result (in ppm) in just a few seconds.

Check Cleaning Agent Ingredients

If you find these are common problems when you check your pool, it is also worth looking at the cleaning agents that you are using.

Check to see their key base ingredients. Many of these will identify what chemicals they use and if it’s a copper-based product, then it likely confirms the staining is caused by copper.


Lastly, you can distinguish copper stains from other metals because they give off different colour streaks. For example, iron stains give off a green or red streak whilst manganese leaves dark purple marks scattered throughout the pool.

Removing copper stains from your pool

Thankfully, there are several easy ways for you to remove copper stains from your pool without having to do anything excessive.

These tricks will help prevent you from having to drain the pool entirely and spend hours getting it back into mint condition.

Using Chelated Cleaning Agents

One of the easiest ways to remove copper stains from your pool is by using special cleaning agents known as sequestrants.

These products use chelated forms of chemical compounds to combat metal stains. This essentially breaks the ionic particles down and forms small clusters of them for easy removal.

As these clusters group together, the stains become much easier to lift and remove using a filter machine or pool vacuum.

Just remember to keep an eye on the chemical levels in the water when using these products as you may need to add an acid-based agent afterwards to bring the pH level back to the ideal range.

You may also wish to look into citric acid stain removers, as these have been shown to be effective at treating copper stains.

Stain Prevention Chemicals

If you are looking for a more chemical-free approach to prevent staining, it may be wise to regularly treat your pool with a stain inhibitor.

Stain inhibitors work by breaking down any metal compounds that may be sitting in the water without the need to add an extra chemical to keep pH levels neutral.

Many of these also prevent limescale from developing on filtration systems allowing them to remove unwanted products all year round and eliminate the risk of staining.

However, this is something that should be done every 6 months if this method is to be properly effective in preventing stains from occurring.

Regularly Check pH Levels

If you think that you might be at risk of developing copper pool stains, always monitor the water’s pH closely.

Copper stains will appear whenever the pH levels start to climb as the metal particles oxidise. This generally happens whenever the pH level goes 8 or higher.

Swimming pools should generally have their pH levels sitting between 7-8 if you want the water to remain clear at all times.

If you do notice the pH levels are not at the right range, adjust the chemical levels in the water to bring them back to the 7.5 mark.

Carry out water tests

If you are worried about the quality of your pool water or haven’t checked in a while, it may be a good idea to test the quality of it.

This can be done in two ways: purchasing a home test kit or taking it to a pool specialist who can examine it.

Home kits can be a quick way to do it if you know how to carry it out and then you can assess what may be the best way to treat the issue.

If not, getting a specialist to test it will help guarantee if you find traces of copper in your pool water and what may be the best products to get it removed from the water.

Eliminating copper for good

As you can see, discovering copper stains in your swimming pool is not as bad as it might look. Despite it being a common problem, there are plenty of products that can remove the stains over time, without draining your water.

Remember, preventing copper staining from occurring is easy particularly if you keep on top of basic care - such as maintaining pH levels and treating your water regularly.

By doing this, you won’t have to worry about seeing discoloured patches in your pool and dealing with those pesky copper stains!

Louis from Pool Advisor


A chemical engineer by trade, Louis is committed to debunking myths in the pool industry by explaining the underlying chemistry and making it accessible to all.