If I have 15 gallons of distilled water, how much H202 is needed with what strengths? Which is best?

I am inquiring because I think I have root rot because of abit of green slime at the bottom of my tank and I change it every week so it's not a long term buildup of anything.

I also ordered Cannazym, but until that gets here; I have to use other means for now.
immortal420 Reviewed by immortal420 on . H202 If I have 15 gallons of distilled water, how much H202 is needed with what strengths? Which is best? I am inquiring because I think I have root rot because of abit of green slime at the bottom of my tank and I change it every week so it's not a long term buildup of anything. I also ordered Cannazym, but until that gets here; I have to use other means for now. Rating: 5