question re: brown algae in new tank

[dsa_mom]

this tank isnt really mine, its my daughter's, but i'm looking over her shoulder all the time to support/advise/etc.
so the question is, her tank is two months old and has finally "cycled" (whew) but now there is brown crud over the glass and sand. No live rock, just some regular rocks and 4 damsels in a 37 gal.
will this stuff go away or does she need to consider some kind of cleaning crew. thanks

 

[fshhub]

a cleaning crew is advisable(if the tank is completly cyled), and the brwon stuff is more than likely diatoms, which are normal in newly cycled(or almsot cycled) tanks,
but can you post your water parameters, particularly ph nitrites ammonia and nitrates and phosphates, these may hel pa bit too

 

[twoods71]

If the brown crud looks like a dust or film then it is probably diatoms.
Diatoms need silicates to survive and silicates are a normal product of the cycle.
If no new source of silicates are introduced to the tank then they will eventually die off.
To speed up the process remove the dieing diatoms as they will add some silicates back into the water.
Here is a link to a post I wrote a while back that mentions diatoms as well as other algaes.
<a href="https://www.saltwaterfish.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=12&t=009964" target="_blank">Algae info here</a>