You will see how this works when you start running your own tests. We have a recommended range for your pool derived from your test results, and as long as you stay within that range everything should be fine. For example, lets say your range for FC is 4-8ppm. Day 1 you test at 4ppm so you use PoolMath and add enough bleach to hit the top of your range, 8ppm. Next day you test 6ppm Still within range so you choose not to add any bleach. Day 3 you are back at 4ppm so you bump up to 8ppm again. Depending on your pool you may not have to add bleach every day, but you do need to test FC and pH every day until you really know your pool's habits.