Here's a great thread all about that. It speaks to many other types of dosing other than Red Sea here as well. Please dont forget to always try to search the forums before asking a question as you may find the answer is already there.
Been dosing red sea alk and calcium the other day went to refill dosing container and noticed a crust forming on bottom of container. Is this normal will it clog dosing tube. Should I shake container every couple of days?