It's 3300 gallons I have a hth 3 way test kit that test ph chlorine and bromine. My ph is at 7.5 but the other two are at 0 I'm assuming since there was no color after adding drops. I have not put anything in water yet. What should I start with? Or should I just add 1 lb shock and its good? I have big round tablets that go in a skimmer but I am not sure I can use with the size of my pool please help!