I buy some chemicals in bulk because it is more economical for me (example, I buy 50 lb bags of calcium because my fill water is processed by reverse osmosis where I live so it is very soft) but other chemicals that I use infrequently (such as baking soda or stabilizer, which I need maybe once a year or less) I buy in small quantities. I do buy Muriatic acid by the 4 gal. case since it is cheaper and I have a SAFE place to store it. This is about a year's supply for me if not more).