When a pool service company closes the pool, they add their chemicals right then, without circulating them. I intend to shock (with bleach) and filter my pool the night before they come. At that point, they'll need to get into the pool to take out the ladder, stick their arms in the water to put on the aquador and such...is it safe for them at that shock level? My CYA is 50, so I've kept my FC at 4, and will shock to 20....thanks. :-D