Based on what we read in here, we just bought the Fluval water polishing pads at Petco and they work great! For under $6 you get a box with six large pads which are "extra thick micro-fine polyester pads" and they look like they will keep us supplied for a very, very long time. Just tweezered out the old filler, cut a very small piece of Fluval, rolled it between my fingers, placed a few drops in the empty card, slid in the new filler, cut off any extra at the top, pressed it down a bit into the cart, added a few more drops (about 8-10 in all), and kicked off. Fantastic! Lotsa smoke. Easy draw.