Brown stuff?

[CluelessScot]

whats this on my rock lol?

 

[Angel Lady]

Looks like food residue and algee mabey a mixture of both.

 

[CluelessScot]

no fish in the tank at the mo. only been up and running bout 48 hours. think its algea?

 

[The-Wolf]

it is diatoms.
these are often seen in new set ups and is perfectly natural.
Diatoms are caused by lack of light, so having the current ligths
on for longer or adding more light will stop it.