I have been researching the BBB method and I am unsure of one thing, does the bleach replace the chlorine tabs or is it used along with the tabs? I think it replaces the tabs but want to be sure. Also I was price checking the BBB products vs. There pool store counter parts and found that typically a 4 lb. Box of baking soda was more ($17) than a 5 lb. Bucket of alkalinity up ($13). but kept searching and found a 12 lb. Bag of baking soda for ($7). Where is a good place to shop for these products? I was using amazon