The other thing to keep in mind is what a lot of people call fireflies, are not fireflies at all.  If the specks are small white specks, they are not fireflies.  Fireflies are usually red, and very large.  They can be white, but they will be larger than normal.  Also, they grow in number over time, usually bunched together. 

This isn't to say that you don't have them, but be sure they are fireflies first.