I tested and compared ph readings (7.4). As in the past, I have raised the pool back to shock level once more. Maybe I'm missing something simple.. Thinking to hard as they say. I've maintained shock levels before for over 48 hours. Over the last 2 weeks this will be 21 gallons of bleach. I only had time to do a quick test this morning.. Ph is 7.2 at 30- shock level, added 3 more gallons of Clorox. I will retest after work