Well, I took the plunge yesterday. Got four 40# bags of the stuff MedVampire recommended from Lowes ($4.43/bag) and dumped in in both the skimmers and into a leaf net over the side. I noticed a difference immediately! Verrrry nice. I am assuming my salt ppm is around 800 ppm (per the BleachCalc app). I took before and after water samples that I will try to get tested today at the pool store. Not sure if I'll add any more - I can't believe the difference it made - especially with my hair - no more nasty tangles after a swim. I did see the temp drop 2 degrees - it was wild. I have a floating digital thermometer that read 80 all day yesterday - as soon as I put the first batch of salt in, it dropped to 78 before my eyes. Pretty cool science experiment!