How to Identify and Remove Pool Stains

Pool stains are not as simple as debris to remove from your pool, especially if they are metal stains. Unfortunately, even a perfectly balanced pool that is well looked after can acquire stains. So, do not be disheartened if your water is clear but there are stains on your pool floor. Luckily, the majority of pool stains can be treated with a stain remover - the only challenge is selecting the right one. 

Furthermore, once you've removed your pool stains, steps can be taken to prevent future stains from appearing.

What is the cause of pool stains?

The first step in pool stain removal is determining the cause of the stain. Pool stains generally fall into two main categories:

Organic: Leaves, berries, and other organic debris can leave stains if they’re allowed to settle and leave too long on your pool’s surfaces.

Metal: Several types of metal can accidentally be introduced into your pool. Maybe the copper pipes in your water system have corroded, or perhaps a metal item was left on your pool floor for too long. Rusted metal accessories, parts, and equipment can also cause stains.

Once you determine what type of stain you have, you will know which type of pool stain remover to apply. The best way to identify which type of pool stain you have is to observe the colour.

Greenish-Brown Stains:

These are most likely organic stains caused by leaves or other plant matter.

Reddish-Blue Stains:

These are more than likely from brightly coloured berries. If you have berry-bearing trees or bushes near the pool, they’re the most likely cause.

Blueish-Greenish-Black Stains:

These could be caused by organic matter like leaves or berries. But if there’s nothing like that around your pool, they were likely caused by copper, which can be present in well water. If you have copper piping anywhere in your plumbing system, it may be corroded, which can also cause stains.

Greenish-Brownish-Red Stains:

This combination is an indication of iron in the water. If you fill your pool with well water, it’s highly likely that it contains iron. Or perhaps you have iron somewhere in your pool area, such as a fence. If it rusts, and the rust makes its way into your pool somehow (when it rains, for example), you can end up with stains of these colours.

Brownish-Blackish-Purple Stains:

This dark colour combination is caused by manganese. This naturally occurring metal is present in well water, but can also be found in municipal water supplies. The water is treated to reduce the amount of manganese, but it’s not completely removed.

Removing Pool Stains:

How To Get Rid of Organic Pool Stains:

Generally, chlorine is the solution here. However, now that we know your 'standard' chlorine levels do not provide sufficient chlorine to combat the organic stains, you'll need to shock your pool. Below is a step by step guide to help you remove organic pool stains:

1. Test and balance the water: Use test strips or a liquid test kit to ensure the alkalinity is between 100ppm and 150 ppm and the pH is between 7.4 and 7.6.

2. Shock the pool, following the instructions on the product packaging. We always recommend shocking your pool at night.

3. Brush the pool.

4. Run the pump overnight.

5. Brush the pool again for best results.

6. Check the stains have disappeared. If not, repeat the process.

How To Get Rid of Metal Pool Stains:

Metal stains can be a little more difficult to get rid of, but it’s not impossible. Here is our method for removing metal stains:

Test the water for metals: It’s a good idea to find out what kind of metal has stained your pool. It can make a difference in the type of pool stain remover you need to get. Some home test kits will test for metals, but your best bet is to take a sample of your pool water to your local pool store and ask them to test it for you.

Get a metal pool stain remover: Look for one that targets the type of metal that’s stained your pool.

Follow the instructions: Each pool stain remover will work a little differently, so follow the manufacturer’s instructions to ensure the best results.

Preventing Pool Stains:

Now that you know how much work is involved in removing pool stains, you'll want to do your best to prevent them.

How to Prevent Organic Pool Stains:

1. Keep the pool water balanced at all times, especially the alkalinity, pH, and sanitiser levels.

2. Keep the pool clean by using an automatic pool cleaner or by manually vacuuming on a regular basis.

3. Skim the pool surface often to keep leaves, twigs, and other organic debris from sinking to and settling on the bottom of the pool where they can stain.

4. Move plants that bear fruit away from the pool area. If you plan to do some pool landscaping, make sure you plant fruit-bearing trees and shrubs well away from the pool.

5. Check the pool regularly for stains. The sooner you find them, the better.

How to Prevent Metal Pool Stains:

1. Test your water source for metals. If they’re present, use a hose filter when filling or refilling your pool.

2. Use a metal sequestrant in your pool. This chemical binds with metal particles to keep them from settling on pool surfaces and to make it possible for them to be removed by the pool filter.

3. Maintain your pool plumbing. If any parts of it use copper pipes, check them regularly for corrosion, and replace them when necessary.

4. Keep the pH level in your pool regulated, especially if you have copper in your water. Low pH makes the water acidic, which will corrode and eventually oxidise the copper, causing stains.

If you're struggling to tackle tough stains in your pool, you can always reach out to a local pool professional using our Dealer Locator.