Wondering why my plant seems to easily over water!

I am growing in a 7-8 gallon black pot, I also have the 5g yellow bucket. There are many drawing holes.. however bottom must be staying wet longer.. ton the the 4 day, I think she needs for a good water. However I give her only a half a liter and seem to have over watered. The drainage should be great I have a three-part soil with compost. Some perlite. I started to have some gas so I use some hydrogen peroxide. This should have made vigorous gross as it did on the other plant. Could this because there was a serious Gant issue of larvae and that's what it's working on. It seems to be coming around within 12 hours. I can attach a photo they're just drooping leaves
Picture provided is of hours before