1. 6.1 and 7.3 are pool store readings. Can't trust them. You can only trust Ben's readings with his kit. If your chlorine drops at night, yes you are fighting something.

2. I would worry about the TA later. It is not causing your pool to be cloudy.

3. I will let mbar help you from now on as I don't want to confuse you with anymore recommendations as your pool is giving you enough trouble already.

Good Luck