I think the green is what is used in the white spot cure, what strength is it? I haven't used that stuff for years but im sure someone will know!
I always get rid of the whitespot by adding rock salt to the tank, I believe the salt is alot better because it is natural, doesn't harm the filter and you don't really even have to add charcoal or worry too much about getting it out, also it doesn't stain the silicon