Vinyl pool liners are your first line of defense to your pool’s health. When you let debris into the pool or leave the water chemicals imbalanced, the liners will have nothing to protect them. Ever noticed black stains on vinyl pool liner? It is one of the signs that things are not as good as you may think.

Black Stains on Vinyl Pool Liner

You are in perfect timing as this post will tell you more about black pool liner stains. You will know how to diagnose the problem, how to prevent them from spreading and removing the stains. Read on and keep your pool spotless.

Black Stains

The black stains happen for several reasons. They are categorized depending on what is causing them. The two leading causes are black algae and metal stains. There are different approaches to remove each of the stain types.

  • Black Algae

Black algae will dot the liner in black spots. These organisms are tough and have a thick coat to resist chlorine effects. To remove them, start with a rigorous brushing using a nylon brush. The resistant coating will become weak and break. Go ahead and test the pH level of the water. Work on the balance to be at 7.2. You will be helping the chlorine to do its job effectively.

What follows is super chlorinating your pool water and using an effective algaecide. Use the algaecide as per the recommendations of the manufacturer. Using it in excess will result in a foaming problem. Keep on brushing the liner to help the algae break down. Use the appropriate vacuum to remove all the dead algae. Resume on normal chlorination once all the black stains are no more.

  • Metal Staining

Your pool water source can bring in manganese, iron and copper into the pool. These metals form oxides that will react with chlorine. It is when the oxides precipitate that you will notice black stains on the vinyl liner. Typically, the stains are black, but in some cases they appear as gray or brown or can even rust. The copper oxides can come from the fittings.

You should do a quick test to certify that you are dealing with metal oxides. Select a small portion of the pool and treat it using a pH reducer. If the stains disappear, then you are positive it is a metal oxide problem. You can treat the rest of the stains using the same method.

Another Cause of the Liner Stains

It may not always be black algae or metal oxides causing the stains. Dye-producing organisms may be the culprits as well. These organisms will pitch camp at the backside of the pool liner. When they release the dye, it will wick through the liner’s fabric and form blotches.

Bottom Line

Black stains on vinyl pool liner are not the best sight. They are telling you that something somewhere is not alright. Find the problem and work on it using the methods discussed here or find yourself a self cleaning pool. If you do it right, you should not have any black stain problems and will be able to keep your pool clean. Always make sure you know the cause of the stains before trying to remove them and follow proper pool care suggestions to maintain your new pool or newly renovated pool.