new set up

[paulhoff]

hi all. just checking, were setting up our first marine tank at the moment. we have 20kg of live rock and some live sand in a 240litre tank. its been cycling for about a week or so and we have noticed there is a brown layer forming on the sand and top side of the rocks? is this just a normal part of the cycle or is something wrong? only had the lights on for 5 hours a day if that matters?
thanks

[Amphiprion]

It is fairly normal and typical for such a film to develop. It should subside eventually as processes complete and nutrients are sequestered.

[jwddboy]

Yeah agreed with above. If this happens it can last.
But in all in a marine tank often gets a browny algae build up.
Nothing to worry about, can still look amazing with the right fish and the right live rock growth (or coral).

[severum mama]

It's unsightly, but not really anything to worry about. Like amp said, it often goes away on its own and is common in new tanks. Welcome to AC! :)

[paulhoff]

thanks.