Shocking the bucket full of water was good thinking--but what did you shock it with? Keep in mind that "shock" is a verb, meaning to raise your chlorine level, instead of a noun, i.e.a particular product. Many stores package either dichlor or cal-hypo and call it "shock", which really confuses people. IF it was cal-hypo you used, it's famous for not dissolving very quickly and can cause milky water problems, especially if you use too much.

Good idea on the prefilter, too........

The words "in check" from any pool store personnel are worthless--you need solid numbers. If they can't give them to you, then you SURELY don't want to take their advice!! You really need a number for alkalinity..........

Janet