No. You don't just want stuff to eat the diatoms, you want to find out why they are there in the first place. How often do you feed? and how much? Also, is it a dusting or is thicker? If it just looks like someone baby powdered your tank, then it is probably diatoms. However if it is thicker it could be cyno. Just seems like a weird problem for a tank that has been established that long. Anything added recently like live rock or anything?