Water Test Report Card: PH Fail

So here we are at Day 10 and my ph is shooting for the stars, but all the other levels are ok.

PH - 8.4, 8.4!
Ammonia - 0
Nitrite - .25
Nitrate - 0

Out of the 20 fish I added yesterday, I think maybe three remain. Doubt they will make it to the morning. What a waste, I should have tested the water first.

At this point I feel like I need to do something about the ph level and not let nature take its course. I wonder if the algae killer had something to do with the ph because it jumped a whole point?

SOLUTION: lemon concentrate. You know, that stuff you add to tea or use to make lemonade with? That's the stuff. I added 1/4 of cup, wait 24 hours, test the water and repeat until the PH is at a safe point enough.