How To Remove Yellow Stains From A Pool Liner – Complete Guide

Have you noticed yellow stains on your liner, and more exactly a yellow coloration of your water line? How to avoid these spots? How to get rid of it?

The water line of a swimming pool is a very sensitive area (especially when it is equipped with a liner). This is where most of the pollution is concentrated, resulting in a brown or yellow coloration of the water line.

The fouling of the water line of the swimming pool is slow and regular. It is caused by fatty substances floating on the surface of the swimming pool, including, in particular: the fallout from the combustion of hydrocarbons (chimneys, proximity to a road or an airport, etc.), body oils and pollution linked to the plant environment.

It is frequently observed that the water line is more easily marked on the sides of the swimming pool, exposed to the sun . In fact, the pollution of the membrane is activated or aggravated by solar radiation.

A yellowish coloration on the water line of your swimming pool may appear.

This coloring results from an undesirable chemical reaction between certain anti-UV agents incorporated in sun products (such as Benzotriazine and Benzotriazole) and the presence of copper in the swimming pool water.

This coloring is limited to the water line (emerged part of the liner) because it is on the surface of the pool that the sun creams and oils, which are insoluble in water, float.

Products That Will Clean The Yellow Stains

  • Regular maintenance of the liner water line

The coloring of the water line is easily removed by a weekly maintenance , using a liquid, non-abrasive cleaning product (varnished membranes), provided for this purpose.

You can also use a magic eraser to scrub your water line.

  • Beware of limestone on the walls of your pool

The lime deposits on the water line of your swimming pool facilitate the adhesion of fatty substances and complicates its cleaning.

Lime is easily removed by using a suitable acidic cleaning product 

It is also possible to use a mixture of isopropyl alcohol and water (1/1). Very stubborn pollution is generally removed with ethyl acetate or THF, but these modify the appearance of the surface (shine) and also remove the varnish and the pattern, in the case of a coating printed or varnished. The use of ethyl acetate, THF or, more generally, PVC solvent, is therefore strictly prohibited with varnished and / or printed membranes.

  • Watch out for copper and sunscreen in your pool

Avoid an excess of sunscreen and especially sun oil (the worst!) And take a shower before swimming.

Avoid adding copper to your pool (copper sulfate).

How To Eliminate The Yellow Stained Water Line For Good

In order to remove the yellow stains on the liner or the PVC membrane, the following curative treatment must be carried out:

1st week:

1- Increase the water level of the pool to cover the stained area

Day 1 :

2- Perform shock chlorination at 10 ppm of free chlorine

3- Adjust the pH of your water to 7

4- Pour into a skimmer 1 cap (40 ml) of metal inhibitor (FERAFLOC) for every 50 m³ of water

Day 4:

5- Pour a new dose of 40 ml of FERAFLOC for every 50 m³ of water

Day 7:

6- Backwash the filter

NB : Let the filtration run continuously, throughout the treatment and repeat the above operations for 5 weeks.