Algae Flakes?

[ister98]

For the past few weeks, I've noticed small brown "flakes" on the surface of the sand and some that sticks to the side of the tank. I've always had an algae problem with my 2 year old reef tank setup. Water parameters are fine and I change water every two weeks. Other than these flakes and algae problem my corals are blooming. Does anyone has any idea what these "flakes" may be?

I've posted a picture in my photo galery so you can see what I'm talking about ...

Thanks in advance for your input.

http://reefcentral.com/gallery/data/561/99006IMG_0998_flakes.jpg

[Sepeku]

It kinda looks like diatoms.

or, on a long shot, some flat worm.