These are the cartridges...
, November 3, 2010
These are the cartridges you need to refill the Plumix. I got the blue-black
refill cartridges and thought ink came out looking a bit too gray.
You could also flush out the empty cartridge and refill using your choice of
bottled fountain pen inks (which come in a huge variety of colors) with a blunt
tipped syringe (I went to the local pharmacy and asked for a syringe with the
sharp removed). I have heard that you do need to keep the little purple disc in
the cartridge to maintain proper ink flow.