PH was 8.4 according to the freshwater fish take test strips I got.

This is water that I have had sit out for 2-3 days roughly and I use old (rinsed out) 2 Liter pop bottles to let it sit in.

I assume 8.4 is a bit of a problem. How much of what should I add to it to make it the right range?

I didnt test drain water since I figure this will be an issue.