@CarlD: mary jo's pool's CYA is 150 and the CH is near 700.

@mary jo: What CarlD seems to be getting around to is:"If shocking the pool worked in the past, might as well shock the pool now" which is your plan. Watermom's suggestion of using polyquat 60% is probably a good idea too. Are you going to have the pool guys winterize the equipment again this year or do you plan to do it yourself?