Quote Originally Posted by RavenNS
I had my pool at 30ppm with cya at 30 recently (possibly fighting algae... it was cloudy water), anyway, it did not bleach my dark blue liner. Guess I got lucky
At 30 ppm FC and 30 ppm CYA, the actual disinfecting and oxidizing amount of chlorine (HOCl) is 2.5 ppm which would be equivalent to having 5 ppm of chlorine in a pool without CYA (at a pH of 7.5). So while that it is on the high side, it apparently isn't in the range that causes bleaching to occur. Perhaps one needs 10 ppm or higher FC "no CYA" equivalent before that happens.

Or maybe you were just lucky!

Richard