Quote Originally Posted by RavenNS
Yes it is "safe" to bring the chlorine levels up much higher than 15ppm ( although most people wouldn't want to swim in it..lol)
With a vinyl liner and a CYA of 40, it is NOT "safe" to bring the chlorine levels up much higher than 15--you run a really good risk of bleaching out your liner that way. Keep it at 15, and adjust upward according to the best guess chart only if your CYA level changes.

Janet