Live rock changing colors?

[lorenz0]

The tank has been running for 4 weeks. In the first week I filled the tank with water and than added sand a week later. Than added the live rock a week after that and it went was only out of the water for 30min. The only thing my tank has that is exposing the rock to air is where the fuge is. That is also where it is mostly white. The rock was also covered in feather dusters and now there seems to be none. hope this helps out a bit more

I also have snails and 10 hermits in the tank already