h2o2 troubles?

ok, back in trouble again (see previous trouble here https://www.rollitup.org/marijuana-plant-problems/419737-newbie-ph-troubles-2.html).

So I was mixing up a fresh reservoir for the one plant that looked like it had completely recovered from my noobery. I used 0-11-22 (ml of grow-micro-bloom GH flora series) and got a tds reading of roughly 425ppm, added 70 drops of pH up and got a pH reading of 5.9. I then added 35ml of hydrogen peroxide 3% to my 3.5g reservoir, plugged in the air, and stuck my plant in it.

I noticed that the bubbles were fizzing, and I figured it would be harmless for the roots since you can use this stuff on your skin. I also wanted to kill any baddies living in the roots themselves.

Anyways, I looked in there half an hour later and I noticed that the leaves look a bit limp. I pulled down on a branch, and sure enough, it didn't resist like it usually does. My first reaction was to pull the plant and put it back in its old reservoir (which I kept on the side for just this sort of emergency).

Any ideas guys?

My setup:

3x3x6.5' tent

600w Lumatek ballast w/ Lumatek high PAR HPS

4 black buckets with 5" net pots and hydroton

GH dual diaphragm air pump (3 buckets) + 2 smaller air pumps (1 bucket)

6" Valuline fan

6" cool tube w/ ducting

Temps: 75-81F canopy

Strains:

Permafrost
G13
Cheese
Blueberry Indica
Northern Lights
Skunk