pH Effects

The joint study investigated the effect on vinyl of water pH between 2.0 and 10.0. A total of 224 white, blue and black vinyl samples were exposed to the ambient temperature and water at various pH levels between 2.0 and 10.0 for an extended period of time. During the test period, the total alkalinity in the test water was maintained at 150 parts per million, calcium hardness was at 100 ppm and the starting cyanuric acid concentration was 100 ppm.

Tests were conducted with the free available chlorine maintained at either 1.5 ppm or 20.0 ppm (The low value was used because it reflects common sanitizer usage levels; the high value was chosen because intermediate levels had limited effects on the vinyl. Throughout all investigations, pH was observed as the more significant variable.)

The effects upon the vinyl of water pH in the 2.0 to 10.0 range were determined with the free chlorine maintained at 1.5 ppm. The results were as follows:

Exposed samples where pH was maintained in the 7.0 to 7.5 range exhibited no adverse effects on the vinyl.
The lower the water pH drops below 7.0, the greater the incidence of wrinkling, loss of tensile strength, elongation and fading. Low pH (the acidic range) was found to have a more adverse effect than high pH (the alkaline range).
As the pH increases above 7.6, the vinyl loses weight and expands.
The lower the water pH drops below 7.0, the greater the vinyl’s weight increase.


It is important to note that the vinyl material remained functional throughout the tests.