there are too many pretty bottles with more uses than i can think of for reef tanks, i don't think they sell it to help us, i think they sell it to make money.of course they probably do something, but nothing a little time can't do also. of all the time we all spend reefing, even the ones that tap out early, cycling is just a very small fraction of it.i don't have money for all the pretty bottles, and have learned that patience is the best way to go.i use pickling lime for my calcium and alk, when either needs a boost i whip out the baking soda or dow flake, i also use epsom salt for magnesium.i'm not the most dedicated reefer, YET, but i choose to stay away from the pretty bottles.