I can/will make your pH rise really fast if you dump too much in at once. It must be dripped into the system. I tried it, but it was too much of a hassle, plus it couldn't keep up with my systems demand. You can only make the kalk solution at a certain strength.....2 tablespoons per gal max. So, if you are using kalk as your top off, you have to hope the amount of water evaporated and replaced by the kalk solution is enough to keep your alk and calcium levels steady.