You can even spot dose the Excel with a syringe directly on the hair algae in the tank, it will kill it off. Do it for a couple days, and when it starts turning color, it's dying.
For java moss, I've done 1:10 and it works well. 1 part Flourish Excel to 10 parts water. And let sit in the solution for 3 minutes, then place in the tank without rinsing.