No prob! Had that same issue myself back in the days of my first bubble buckets.
It'll help. The green you got won't go away I don't think but it won't get worse and won't hurt anything (at this stage) if you tape it up.
H202 works, I've used it, makes roots explode too, but I'm a fan of beneficial bacterias (I use hydrogaurd). Really the algae is not an issue tho. I have it pop up all the time, especially when light gets to the res. But by all means, just don't add too much and if I remember right you have to add it every 2-3 days... It'll also take all the color out of your nutrient mix, don't panic it's fine lol