I think they are one in the same. To-ma-toe...To-mat-o...etc..etc..etc.
I have refilled my filters for years. Still using the same inline cans I bought in like 2006...and am on probably the 4th refill (?) Fuck..I don't keep track.
Anyway...there is carbon/charcoal for refills on ebay...and your local hydro shop may also be able to order it.
I can't speak too the newer Can filters..i >hear< they are WAYYYY lighter than before. The HEAVY ones use the pelleted charcoal/carbon pellets that are about the size of rabbit food. I suspect, if they are lighter these days, that they have switched over the the GRANULAR carbon...supposedly from austrailia (R-47 or some such shit) that makes like PHAT, PHRESH, RHINO, etc,,etc,,etc, use in their far filters.
I would look for the granular.....and for free shipping (!). I don't believe for a second the stories that you cannot repack these filters as they do in the factory. I have tried and tried to find the pic....and someday I WILL....but when I had my hydro store and these first came out, I saw a picture from the PHAT factory of their "packing" machine and it appeared to be an ABORIGINAL KID ABOUT 10-12 years old with a huge pile of charcoal behind him...the shell of a filter before him... and a goddamn RUBBER MALLET in his hand. o_O
suckers. :D
good luck however ya go