Water balance and Vinyl Liners

Recently, one of my colleagues suggested I review an article about water chemistry and testing which focused on the effect of un-balanced pool water on vinyl liners. It concluded that balanced pool water has a major effect on the longevity of a vinyl liner in a swimming pool. I thought it important to pass on a summary of what was learned through the testing process.

We all know that water balance is important to the performance of the sanitising chemicals used in a pool, as well as for water clarity and comfort of the swimmers. However, water balance is equally as important for the life of your pool liner.

Using standard parameters of total alkalinity of 150ppm, calcium hardness at 100ppm and the starting concentration of cyanuric acid at 100ppm, a series of tests were conducted with different types of chlorine and PH levels ranging from 2.0 up to 10.0. Here is what was discovered…….

Samples with free chlorine at 1.5ppm where the PH was maintained between 7.0 and 7.5 (the Aust Std is 7.2 – 7.6) showed no adverse effects. The lower the PH dropped below 7.0, the greater the fading, wrinkling and loss of strength in the vinyl liner, plus it increased in weight (likely from water absorption which is what causes the wrinkling). As PH increased above 7.6 the vinyl lost weight and expanded. Samples with free chlorine at 20ppm where the PH was maintained between 7.0 and 7.5 showed colour change where white turned yellow and blue faded and became dull in colour. This high chlorine concentration caused wrinkling as well.

What this tells us is, it is important to maintain water balance to maximise the life of your pool liner. However, the study also revealed that even though the look of the liner changed with exposure to extremely bad chemical levels, the vinyl still remained functional as a pool liner!

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