From the Net...
Whirlfloc is a purifed form of high molecular weight carrageenan extracted from red marine algae (Rhodophycae) and manufactured exclusively for use as a wort fining agent. It accelerates the formation of dense and compact hot and cold trub, saving time, boosting wort recovery and resulting in considerably brighter worts.
Yes its a secondary. This was 1 week primary 2 weeks secondary.
I tried to make sure I cooled this off as fast as possible. I don't have a wort chiller yet, so I used an ice bath and a couple sanitized frozen bottles of water. It was by far the best cold break I've had.
Oh and I dumped everything in the primary break and all.
This was my first attempt. Its a bad picture but you get the idea.