Hmm, try see if you can get a buddy with one of those touch phones to take a photo of the algae for you. The cameras on those things are pretty sharp. It sounds like you might have a few different species of algae, or possibly not cladophora. It would be helpful to know exactly what species you have since not all of them react the same way with H2O2. Either way it won't hurt to try it out when you finish finals.
Good luck on finals by the way I know that time of year can be stressful, especially if you are taking any science courses.