Pool liner : usefulness colors maintenance – The complete file

The liner is a very important element that is expensive. It must therefore be the subject of regular maintenance but also periodic monitoring. At the slightest color stain it is necessary to react to prevent the problem from spreading, which may require the entire coating to be replaced. Let’s find out what each stain color on the liner means and let’s see what the preventive and/or curative actions possible.

What is the pool liner used for?

The liner is not just there to look pretty: it is what seals the pool. This flexible PVC coating (reinforced or not) available in different thicknesses must therefore be of excellent quality, but to preserve its longevity, it needs to be maintained. Of course, it is subject to the ravages of time, the misdeeds of certain components of sunscreens, the action of the urine of unscrupulous swimmers, but can also deteriorate with certain water treatment products, if this is too hot, or if it undergoes variations in pH, TH and TAC…

Each problem has an explanation but also, in most cases, a solution.

Stains on the pool liner: each color has its cause and remedy

Various problems lead to the appearance of stains on the liner that take on a very specific color depending on their origin. To be able to apply the appropriate remedy and prevent recurrences, it is essential to know what does each color correspond to stains and know the influencing factors as well as causes responsible.

The table below allows you to know at a glance what can be the origin of stains on the liner according to their color, whether or not there are influencing factors and how to act preventively and /or curative when possible.

Color stains on the liner


Factors that influence the causes of stains

Preventive or curative action




Pool water quality

Purplish-pink (especially above the water line)

*Bacteria between the liner and the wall due to very high humidity under the liner

Without effect

Without effect

Without effect

Without effect

*Treat imperatively BEFORE laying the liner with a disinfectant, as a preventive measure

*For curative action, lower pH to 6 and temperature, but restoration is difficult


*Pollen, *Copper components of certain sunscreens

Without effect

Without effect

Without effect

Without effect

* Raise the water level,

*Carry out a shock chlorination,

*Adjust the pH,

*Change sunscreen


* Some dead,

*Iron oxide

Oxidizing products

Without effect

Too high


*Drain, *Brush clean with oxalic or hydrochloric acid

*Lower pH


Too rapid aging of the water (sun rays, products of all kinds)




Without effect

*Use an algaecide, *Clean manually then vacuum

*Consult a swimming pool specialist because the restoration is complex

Brownish-red and sticky liner

Excess metals (copper, iron)


Temp. = or > 30°C

pH > 8,5


*Reduce the water temperature,

*Lower the pH,

Do a good cleaning


*Heavy metals: copper ions, iron, silver, manganese…

*Anaerobic bacteria due to underlying humidity

Without effect

Without effect

Without effect

Without effect

*Treat with a microbicidal agent and a metal sequestrant

*In prevention, never use copper sulphate but use a flocculant for metals

Gray or white

*Normal if liner at end of life as this is a natural sign of wear

*Also appears early on poorly maintained liner

*Testifies an excess of limestone

Without effect

Without effect

Without effect

Rebalance the TH

*Drain the basin for a total cleaning

*Use an anti-limescale product in case of TH higher than the standard

After studying the table above, we see that the main influencing factors colored stains that may appear on the pool liner are:

  • water quality,
  • water temperature,
  • The pH (Hydrogen potential),
  • The treatment processes or the products used.

It is clear that a swimming pool water analysis must be performed as regularly as possible in order to limit the problems, which does not dispense with maintaining the liner.

How to maintain your liner?

We now know that liner maintenance is fundamental since it is about one of the major components of the swimming pool. Aging inevitably leaves traces, just like treatment products, mistreatment, the sun and sunscreen products, intensive use and even heavy metals, among others.

We evaluate the longevity of a liner very good quality at more or less 12 years on average if it is maintained. This service life is considerably shortened in the absence of maintenance. However, it is necessary to be aware before opting for the construction of a swimming pool, that the replacement of a liner represents a budget which can be substantial. Here are the best tips for maintaining its pool liner in perfect condition for as long as possible.

Maintain optimal water quality taking care to maintain the ideal parametersto know :

  • The temperature, expressed in °C: the pool water must be less than 28°C to limit the appearance of colored spots on the liner.

  • The Hydrotimetric Title (TH): between 8 and 25°F. It indicates the hardness of the water in the bathing pool.
  • The Complete Alkalimetric Title (TAC): normal if it is between 10 and 20°F, it indicates precisely the alkalinity of the water.
  • Hydrogen potential (pH): between 7 and 7.4. This is the acidity index of water.

All these parameters are recommended by specialists, namely swimming pool specialists. As soon as we notice notorious deviations, we do not wait to treat the water because it is absolutely necessary to restore the standard as quickly as possible. To do this, one can use either the brome at a maximum of 2 mg/litre, i.e. at chlorine whose ideal rate is between 0.7 and 12 mg/litre. But beware, contrary to what many pool owners do, the liner must never be in direct contact with the chlorine tablets, as this will irreparably cause stains on the liner or lead to its discoloration. It is recommended to use chlorine solutions specifically adapted to the liner.

Colored stains on the liner: act as soon as possible

As soon as you detect colored stains on the liner, you don’t have to think that they will disappear as they came. On the contrary, it is fundamental to act as soon as possible after having made a reliable diagnosis. Better, for that, ask your swimming pool specialist to come and see the damagebecause this professional is able to find the solution that is needed without risking damaging the liner, a swimming pool coating that is expensive since it takes several thousand euros to cover a large inground swimming pool.

The swimming pool is an element of comfort which adds value to the property…provided it is in perfect condition. This involves almost daily monitoring and maintenance. If you don’t think you have the time to take good care of your swimming pool in the long term, it is better to ask your pool specialist what he offers as swimming pool maintenance contract.

Control visits including the necessary analyses, repairs, wintering and restarting the swimming pool are all benefits who can be included in the contract. The rates vary according to the size of the pool and the services chosen. As an indication, it is necessary to provide according to the contract between 50 and 270 € / month in the majority of cases. A simple connection to a swimming pool comparator allows you to receive several quotes to better compare services and prices.

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