Strobe Light Effect Not Working

I want to use the Strobe Light Effect to make a very fast flickering look on a clip - I was planning on using the random seed to make it look like a candle flickering. However, I can't get the effect to show up at all. The clip is about 1 second long and I have the strobe duration set to .1 sec and the strobe period set to .2 sec. I haven't even gotten to the random part yet because I'm just trying to get the effect to show up, but even after rendering it and playing with the strobe duration and period, I can't get anything to show up. Any suggestions?