A simple 9 volt battery wrapped with a single 26-28 gauge 12" pure silver wire on each pole put in a glass 0 ppm distilled water works for me. Never had a lady not sack-up after spraying her for about (3) weeks, every (6) hours, (3) times a day if your dealing with an auto flower, and every (4) hours, (3) times a day if you are dealing with a photo. You should start your spraying at about (2) weeks into flower for auto(s) and for photo(s) you would start right when you switch your lady over to (12/12). Now most people will tell you that you need 35-40 ppm(s) of CS to get a lady to sack-up, but I have just as good luck with just 15-20 ppm(s) of CS.