Short answer: I think you'll be okay.
It's difficult to tell exactly without actual lux measurements because your tank dimensions and contents enter into the equation. In addition, "reef aquarium" casts a pretty broad net in terms of potential inhabitants.
Lots of people rightfully scoff at the watts per gallon metric, but as a rule of thumb, your value of over 4 watts per gallon should be fine for anemones and some other animals.
It won't be nearly enough for acropora, clams, and other high-intensity light animals.
We recently tried a lighting experiment using 5 Lights of America 65 watt compact fluorescent lamps from Home Depot with color correction on our 185 gal. reef tank. The experiment failed miserably, but none of our corals died...they just looked like they had Seasonal Affective Disorder, like people spending a winter in Oregon. When we went back to our original lighting (around 4 watts per gallon), and everything perked back up.
So keep a watchful eye on your animals. If one of your animals looks like it's getting SAD, try moving it higher in the tank.