I'm probably a month or so away from opening my pool for the first time and am ready to go chemical shopping. I'm going to do the BBB method this year and am looking for an idea of how much of each chemical I should start the season with. I have storage available and don't want to be going to Walmart every week for Bleach, Baking Soda and Borax.I have no idea how much of these per month I will need. What's a good rule of thumb for an inventory of chemicals to start with?