If it s closer to a brown black and is found on the sides of the pool as well then you might be looking at metal.
Brown stains on pool liner.
Scrub the algae with a soft nylon brush.
In most cases this is all that is needed with vinyl pool liners.
Once the algae has appeared onto a vinyl pool liner it is not hard to get rid of but it is a good indication it is time to check the pool s chemical levels.
Doheny s also carries a spray on vinyl cleaner that can be used if your pool is drained.
All natural pool enzymes will eat away at organic material to remove the pool stain with little or no scrubbing and without the use of harsh chemicals that damage pool liners.
Watching the pool like a hawk for foreign objects keeping it clean and keeping it balanced are the main ways to keep stains off of your pool liner with special attention to how you add pool chemicals.
Use a stick or a pool pole not your finger.
The first step to deal with organic materials is to shock your pool and scrub it.
Go to this page to see how to treat your pool for brown algae.
How to remove brown algae stains from a vinyl pool liner by launie sorrels.
Organic pool stains are treated by shocking the pool with a chlorine shock treatment.
If your stain is all around the waterline of the pool because of material floating at the top an enzyme based cleaner will help to break down organic compounds and oils.
If the stain lightens up or disappears it s organic.
Prevent vinyl pool stains.
And brown stains concentrated on the bottom can likely be attributed to dirt stains typically enhanced by calcium buildup.
If that doesn t work try a stain remover.
Mineral pool stains are treated with acidic stain removers.
Preventing pool liner stains requires vigilance.