Is this brown stuff normal?

[kspink]

Hi,
We just started our quarantine tank (10gal with crushed coral bed, a couple of rocks-not live, and inoculated with live sand that had a bonus hermit crab in it). It has been running about 10 days. Our water conditions have stabilized and our ammonia and nitrate have hit zero with the nitrates starting to rise. Do we need to do a 50% water change? Can't remember where I read that at the moment.
The hermit crab was very active for the first few days (he really tore a piece of nori to shreads-neat to watch) and has now taking to hiding, but he molted so I think that was why he was hiding. Any other possible reasons for his sudden shyness? (He did take a flying leap off one of the rocks)
Now our nice white bed is turning brown. Is this normal? What can we do about it? Should we add a snail, if so, what kind? And finally, can we now add our first fish to quarantine before putting in the main tank.
Oh yeah, how big might this crab get? He is white with tan stripes and right now very very small.
Thanks,
Katie

 

[slick]

You don't want anything in your QT except a piece of pvc pipe for the fish to hide in. Reason bring if you have to treat with meds for anything the cc and rock will absorb some of the meds making propper dosing impossible. What did you cycle the tank with?

 

[kspink]

We put in flake food and some nori seaweed to cycle (plus the live sand).

 

[radioactive]

I agree with Slick and Kipass , no substrate unless you are just cycling the tank . keep it clean with only PVC pipe ... good luck

 

[kspink]

ok. But, what about the brown stuff. Would like to know in case is shows up in the main tank as well.
Also, with quaratine lasting up to a few weeks or longer, don't you need some kind of biological filtration? I think we have a small pump of some sort hooked up but I would have to read the box to see what it is.