Don't forget stabilizer. When you get the chlorine and ph at the right levels you need to add stabilizer. Check your chemicals at least once a day. We use the liquid test kits. Very easy to use. Just fill with pool water and add 5 drops of the chlorine tester and on the other side 5 drops of the ph tester. Takes maybe 2 minutes. WHen it's very hot and sunny out, the chlorine is used up faster so you might want to test also in the afternoon.