A pool store should have refills and DE. How many times a day are you testing and adding bleach? Since you are back in town, tomorrow, if I was you, I would test and add more bleach every 3-4 hours throughout the weekend until you get to where you are not losing more than 1ppm of cl overnight. And, run the pump 24/7. Are you watching your filter pressure?

I don't know if you need Borax or not. You didn't list your pH. Actually, post a whole set of current water testing results.