3:1 h202 mix is a bit strong, I would do more along the lines of 9:1. But if you do not see massive amounts of algea, then it is really not going to have a negative effect on your plant. They are not parasitizing your plant, just there because it's the perfect environment for them. They are probablly eating some nutes, but as long as the colony isn't massive, it's a minimal amount.