It's hot pink, what is it?

[Willow]

ok the system has been running with salt for less than 2 weeks. a few days ago i notice that there is a wee bit of "pink' substance growing on the silicone in the fuge section of the sump. yesterday i added 70lbs of live rock to the display. this morning i check on things and notice that the pink as grown quite a lot overnight. it seems to be covering or starting to cover all the silicone in the fuge area of the sump. i leave the area light 24/7 with a 18 watt cf bulb.

does this look like cyno? how could it grow that fast in a new setup? what would have introduced it?