Do yourself a favor and DO NOT do that H202 treatment. You have some very nice fish and there is a good chance you will lose some of them. It's not worth it to get rid of algae. That thread is littered with people who have lost a lot of fish because of that treatment.
Trim as much of the affected leaves as you can, do a big water change, reduce light duration to around six hours for a while. Add carbon/purigen to your filter and make sure the plants have the ferts/co2 they need. Keep up with water changes and see where you are.