This earlier post didn't garner much of a response but I'm gonna' stick it back in this thread just as food for thought. It would be a quick way to enjoy the rest of the swim season
Simplify your life....drain the pool (7k gallons) and truck in water. You will start with a known point, get rid of all the issues in your water, and be swimming 30 minutes after the truck pulls away.

Ben's test kit will help immeasurably with any future issues that crop up.