You need to take your chlorine level up to 20ppms and keep it there. You are fighting something , that's why your chlorine is dropping overnight. You have to be consistant - get your chlorine up to 20ppms with regular bleach, and test 3x a day and bring it back to 20ppms. If you stay consistant, your water will clear faster. Everytime you see it under 20 - add more bleach. You can use the bleach calc to see how much to add.