What is this stuff?

[MizTanks]

http://tapa.tk/mu/18b19601-9708-bbd2.jpg

It's not as bad as this anymore but it's still showing up on the sand bed along with a dusting on the tank walls. I'm cleaning the walls every day.

[demonclownfish]

i would say dino's

[greenstarfish03]

From what I can see I would agree. I get some from time to time pending on how things are going.

[XSiVE]

I think you've got a case of growing corals ;)

[Myteemouse]

I had this problem a few months ago I changed my RI unit filters and a few water changes later I was good.

[MizTanks]

Thanks guys! I'll change my RO filter, see how that goes.