Brown Stains In Pool

Brown Stains In My Pool - How To Get Rid Of Them?

Brown stains appear as unsightly patches on the surfaces of your pool that can make it look unappealing or dirty to potential swimmers. Luckily, brown stains in swimming pools can usually be dealt with fairly easily.

In this article we will discuss the two main causes of this discoloration of your pool, how to determine what type of stains you have, how to remove these stains, and ways you can prevent them from forming again in the future.

Causes of Brown Stains

Brown stains are typically caused by one of two things: organic debris or heavy metal oxidation. In order to treat your stains effectively, it is necessary to determine what type of stain your pool has.

Organic Stains

Organic stains often appear brown in colour and are typically the result of neglected debris or algae in your pool. Debris such as leaves, twigs, and dirt can settle out in your pool and release tannins that affect the colour of your water and leave stains. This debris can also harbour bacteria or algae.

Some organic stains are composed of algae. Dead algae can remain on the lining of your pool, and if steps are not taken to remove it, it can toughen up and form stains.

To determine if you have organic stains, scrub a stained spot on your pool’s surface with a stiff bristled brush, potentially with added chlorine granules. If the treated area shows signs of improvement, it is an organic stain, but if it shows little or no changes, it is a metal stain.

Metal Stains

Metal stains are caused when dissolved heavy metals in your pool oxidise and then bond to the surfaces of your pool. Some heavy metals that can be present in your pool water include copper, iron, manganese, and silver. Each of these types of metal leave unique stains behind.

For brown stains, the culprit is typically iron. These stains show up in a way that is similar to rust. Sometimes, you may have a mix of different heavy metals causing stains in your pool. This is especially likely if you fill your pool with bore water.

How to Remove Brown Stains

Brown stains that are caused by organic debris are typically easy to remove and can often be resolved with scrubbing or vacuuming your pool. For stubborn spots, we recommend a steel bristled brush that can be attached to a telescopic pole.

If you are unable to invest the manual labour in organic stain removal, you can also use a stain remover. The Serious Stain Remover works on both organic and metal stains, making it a great option for pool owners battling multiple conditions at once.

For brown stains that are caused by heavy metal staining, you may want a stain remover that targets metals and other minerals specifically. In this case, we recommend using a stain remover that is effective on multiple types of heavy metals, such as this Lo-Chlor Stain Remover.

By using a stain remover that is effective on the four most common types of dissolved heavy metals in your pool, you are taking a broader approach to stain treatment and are more likely to get your achieved results the first time.

In some cases, you may know that your stain problem is mainly caused by iron. Perhaps you live in an area where this metal is naturally abundant. In these instances, it may be helpful to use a stain remover that specifically targets iron-based stains.

When applying a stain remover to your pool, it is essential to follow all instructions on your product’s packaging in order to ensure that you are performing your pool treatment as safely and effectively as possible.

Most stain removal products require your pool to have a precise chlorine and pH level, and some may even require chlorine removal prior to treatment. After treatment is complete, you will need to rebalance your pool’s chemistry.

Preventing Stains

Whether your brown stains are metal-based or organic in nature, once they are gone, you have the power to prevent them from appearing again. Stain inhibitors are especially useful products that prevent metals and organic debris from oxidising in a way that bonds with the walls of your pool.

We recommend the Serious Stain Inhibitor, because unlike other metal-stain preventing products, this product does not introduce phosphates to your pool. Phosphates are harmless on their own, but once they accumulate in your pool they can become a source of food for algae.

If organic debris is the cause of your stain, ensure that you skim and vacuum your pool regularly to prevent this debris from breaking down and releasing tannins into the pool.


Brown stains may be unsightly, but luckily they are very easy to fix once you have found the right products for your particular type of stain.

Do you have any questions about how to remove brown stains from your pool? Leave us a comment down below, we’d love to help!

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.