Hi, I have some experience with flocs, so if I may chime in

Flocculants (floc) work by coagulating small particles together into bigger (heavier) ones, so that they can either filter out better or sink to the bottom. Your result from the drinking glass test is what you want to happen in the pool. What I have done in the past is add the floc, circulate water for 2 hours (recirculate if you can, avoid running floc treated water thru your filter), then shut off the pump and let everything settle overnight. Next, day I vacuum the debris and settled particles from the bottom to waste. NEVER run it thru the filter, as you will have a mess on your hands, cleaning the filter. I made that mistake the first time, wondered why my filter pressure went up so fast, went to clean it and found the floc left a slimy residue on the cartridge. I can only imagine what kind of mess it would be for a sand or de filter. As far as how much to add, every floc is different. You'll have to follow the directions on the bottle. Also, make sure you adjust your ph to the ph range listed on the bottle for the best results.