Will do!Get a Toothbrush and Scrub the rocks and corals, Do water changes twice weekly, rinse repeat until it gets under control, also vac your sandbed.
I have a 40B also, currently 1.6 years old, believe me, I went through all of it...but hard work and perseverance paid off in the long run. Now, I only do water changes every few weeks, at 10%, and most of the problem algae has died and don't come back.