Overnight Algea

What is this yellowish algea on my rocks and sand? Seems like it came overnight but wont go away. I stir it up and blow it off the rocks but it keeps coming back. It just started a couple of days ago. Water levels are good and I use Ro for water changes. Any thoughts????

 

the picture quality is not that great but it looks like some Diatoms to me.
By simply blowing them off or turkey basting them you are not solving the problem. diatoms are a nature issue for aquarists due to the fact that they thrive off of silicates. Anytime that we start a new tank we are using new plastic that introduces diatoms, this is also why one of the first issues for new aquariums is a brown/rusty slime.

 

Most likely diatoms,will go away when the silicates they feed on are used up.Diatoms are a natural occurance in newly set up tanks or when new sand,equipment,or dry rock, is added.They usually only last a few days to two weeks.