CYA tested to 200 ppm. Yikes! I've been keeping shock level around 35 ppm of chlorine. Yes, I'm using distilled water to dilute, I did a quick check with full-strength pool water and got a deep orange color. As for my liner, it only has a couple years left anyway, is there any other danger to overshocking? I don't plan on jumping in anytime soon Just stocked up on more bleach, in the past 6 days I've added 16 gallons.