what is this

[cusweatin]

why do i keep getting all this brown stuff on my substrate i do weekly water changes with ro water and i do not overfeed the tank has been running about 2months now i transfered most of the stuff from my other tank and this stuff just appeared

[BrianH]

Looks like diatoms to me. This is typical of a new tank.

Brian

[lebloom]

You will see this for a short time since the tank is really new. In awhile it will look really nice. Get yourself some hermits to help it out.

[kreblak]

Diatoms are your culprit. Hermit crabs (scarlett or blue legged) will do an excellent job of sifting through your sand in search of diatoms to eat. Diatoms are part of the normal tank cycle. I still get them in my newest tank, and it's been up and running for over 7 months.