Brown stains in the pool?

09 March 2018

We're often approached by swimming pool owners who can't enjoy their pool because of brown stains in the water. We'd like to explain a bit more about the causes of these discolourations, but we'll also give you the solutions.

brown stains in the swimming pool

The causes of brown stains in the swimming pool

When you encounter brown stains in your pool water, your desire to dive in soon disappears. In situations like this, it's natural for you to want a solution that will help you quick smart. The only way to achieve this is to find out the root cause of those brown stains.

The first possible cause is that the concentration of iron is too high. This iron concentration needs to be under 0.2 mg/L, otherwise iron oxides build up due to air oxidation.

A second possibility is the presence of brown algae. This problem is relatively simple to resolve by performing shock chlorination.

Solution against high iron concentration

The first cause is the most common culprit of brown stains in the swimming pool.

When the iron concentration is too high, it leads to brown water discolouration. It is imperative that this iron concentration is reduced to under 0.2 mg/L, otherwise air oxidation could cause iron oxides to build up, resulting in brown stains.

The solution is Metal Ex Magic. This product removes iron, copper, silver, calcium and other metals from the swimming pool water, without you having to empty your pool first.

Just add 3 to 5 decilitres per 10m³ of pool water. Spread the substance evenly across the entire swimming pool surface with the pool filter on!

Allow the filter to do its work for at least 48 hours and finish the cleaning process with a backwash. After this, the brown stains should be gone.

Please note: if you're using well water to fill your swimming pool, it's very likely that this is the cause of the brown stains in the water. This is ground water, which naturally contains high concentrations of iron.

Solution against high iron concentration