I am not new to pools but new to this board. Just wondering how often you guys shock the pool? What would be a situation that would prompt you to shock? I keep hearing heavy bather load... but what is that? I have a pretty big pool- 20x40 in-ground with 10ft deep end. I have not shocked it since I opened it. Water is perfect. Just wondering if I should just because? With the holiday weekend hopefully the weather will be nice and it will be in full use Fri/Sat/Sun/Mon.