Purple sponge?

[Lukielight]

So im traveling for work l, and my girlfriend sent me this picture of my temporary tank holding some rock and coral. When I left there was nothing. Now it appears half the rock is covered and it started growing on 2 of my coral within 4 days. I assume if it grows on coral its not in any way desirable.

 

[Redfoxtang]

Unfortunately that looks like Cyanobacteria.

 

[andrewey]

+1,
Cyanobacteria

 

[Lukielight]

Makes sense. I had a tank disaster recently and had to shove all my livestock into my sump and quarantine tank before leaving town for work.