I am a newbie. I just installed an above ground coleman 18ft round pool. over 6000 gallons. I just added chlorine to shock it a day ago. I tested it today with a store bought tester that tests the chlorine and ph levels. The red agent tested well and it showed the ph level fine. But the chorine didnt even register. The water didn't even turn yellow at all? Any tips, help and info would be greatly appreciated. Glad to be a member! Thanks!