I needed more acid so just for kicks I bought a water sample in to the pool store to have it tested since they do it for free if you buy something. She tells me that the alkalinity is too high (I knew this already) and printed out some directions that says to add 2 cups of acid per day for 5 days. I'm just wondering, if I need that much acid, then why can't I add it all at one time? Does it not work as well as if you add a little bit every day?