I have a 14x42 pool with filter that pumps 1,000 gallons per hpour. I am not able to keep my chlorine level. I use the test strips and for the last 5 days I get a 0/0 level for chlorine, but ph alkalinity are fine. Please help!!!!! I have gone to many sores to ask questions and no one working in these stores know anything about the product they sell.