Dosing 1.0-1.5 dkh twice a day seems high to me. I had a prior issue with dosing too much, couldn't seem to get cal/alk to not react and create a precipitate crust all over everything espically pumps and what not. I tried to "reset" a couple times.... large water change, measure alk and then measure alk again in a couple days, figure out what the dose should be and start dosing. However each time I started dosing it always seemed to run away- where I would dose what should have kept it stable but levels were still dropping, increase dose, drops faster...etc. Ended up getting calcium reactor which seems to have done the trick for me.