All summer has been green. I'll shock it, get it clear and then within 5-10 days of regular testing and treatment it turns green again. I think I've found the problem. i replaced the rubber tube and fitting over the pipe when I opened but the tabs are taking more than a week to dissolve on full, when it should take about 3 days. I loosened the white screw things on either end in case it was cutting off the flow but that hasn't done the trick either. any suggestions?