You should be able to get distilled water there--if you can't find it with the rest of the water, check the baby section...sometimes the stores here put it there for mixing formula bottles with.

In 10,000 gallons of water, that same 1 gallon of bleach will raise your Cl by 6 ppm. In 11,800, 1 gallon raises it by 5.1. So...you're still in the ballpark, just add what you think you need, test, and then adjust from there.

Janet