I have the same issues. I have been useing only 4 vivi nova since Oct 2012. Started to have leaking issues with all novas, thought it was the center pins also. Found out last night that the O ring at the bottom of tank is leaking on all my nova's the
juice runs around the bottom to the pins that looked like the pins were leaking. Only way the pins could leak if you have
juice going into the wick or the bottom contect has a crack in it, which happerned to me 3 weeks ago and broke off.
I had some very small size rubber bands around, replaced the BOTTOM O RINGS on all tanks so far no leaks! Only two days so far.
Goto Lowes or hardware store, should be able to get a replacement O RING from them.