Congratulations! I have just started to research
SW, and I have learned that lighting is very important to reefs (don't ask me what kind of lighting yet,
LOL!) and
SW tanks need a much greater water flow than
FW. So, I would use the certificate for lighting or powerheads. I have heard that lighting is rather expensive, so you want to plan your lighting carefully so you only have to spend a bunch of money once. But you probably already know that!
Just wondering...where in PA do you live -- east or west? I'm trying to think where I would spend a certificate like that around here!