I've done this on my tank due to having a tonne of GHA and Cyano and a patch of BBA. Unfortunately I don't have any Excel so I just did the H2O2 part @ 3TBS per 10G. After a couple days it was all gone. However I had a bunch of healthy, propagating spiral val that all melted away after this treatment. Funny thing is they were the most healthy plant in the tank. I guess vals just don't respond well to this.