Thanks Karto, but one question. A while ago I bought some at Walmart that is 48%, and at the time I was very careful to buy what I thought was the right concentration and that it didn’t have any other cute chemicals in it. Now I see 78% as the minimum. I plan to keep it still as my backup for chemical purification, in case my brand new bottle of bleach gets too old. Any thoughts?
You would have to add more than a heaping teaspoon full. How much more? I would guess 1 1/2 teaspoon (48 + 24= 72) but that is just a guess. There are some on here more familiar with the chemistry that I am.