ultimately you will need more light for a reef, but for mushrooms or polyps you might be ok.
My mushrooms were fine under a SunCoral 40watt bulb til I could afford a better one.
My polyps did ok, but I had to put them high in my tank. (Normally those guys can be low in a normal 'GOOD' light set up)
Personally, if you want to get soemthing in your tank with lower lighting, you might want to get a mushroom rock. I have mushrooms growing in my tank in CAVES. lol