If your lights are that close, then she looks to be nitrogen starved. She is really light green. That's either a light prob, or an N def. It could also be a host of other things, but those are the most likely. STOP putting H2O2 in there!! I certainly hope you diluted the peroxide.
Since this is obviously your first grow, I'll give you the "newbie" speech. MJ is a plant. Nothing more. In fact, it's a WEED and will grow in just about the most hostile environments nature can throw at her. The biggest mistake every newbie I see makes is to love the plant to death. It does just fine in nature without our help or intervention, and if you give her a medium to grow in, light, and a bit of food, she'll do fine if you let her do her thing without too much interference. The hardest thing you'll ever have to do (besides keeping your mouth shut and not showing her off to your friends) is NOT TO STRESS over every little thing you see. It's a living thing, and will show a "hangnail" here and there. Every wrinkle in a leaf is not a catastrophe that requires your immediate attention.
These forums are a mixed blessing, and can be likened to diving for pearls in a cesspool. We have many experienced people here who will answer your questions, but we also have many idiots with nothing more to do with their time than sit on a comp and try to prove how great they are, and will pass on a whole lot of bad information, telling you only what they have heard (usually wrong) rather than anything based on their own experience. It's up to you to sift the pearls out of the shit.
If you DO have a problem, and bring it to the boards, take whats given to you with a grain of salt, asking your self what makes sense based on science, not folklore. Start reading about biology, and botany, because thats what this is, pure and simple. Everything having to do with growing anything is based in science. Don't try and implement each and every "cure" you see recommended all at once, either. Try them one at a time.
This is gonna be a learning experience, and should be fun, but I know it's very stressful at first, believe me. I decimated my first couple of grows, and have had quite the time getting to where I am today. When I looked at this as a learning experience, and that the joy was in the journey of that learning, I had a much better time of it! Keep at it, and you'll be fine. Just keep things simple at first, hen start getting more advanced. Don't worry about getting 20 pounds of killer weed from a plant, and just concentrate on getting one thru to the end at first.
pH in soil, while it must be taken into consideration, is NOT crucial as it is in Hydro. The soil will buffer anything that get's put into it. It's the pH of the SOIL thats crucial, and with MOST commercial soils, it's well within the guides.