This is about half as expensive per application as the AquaticLife non-woven 100 micron stuff that I use but Drs Foster & Smith carries these
Aquarium Filter Media: Drs Foster and Smith Mechanical filter Media
Note the 100 Micron Felt 30" x 36" x 1/8" thick, CD-79434 is $6.69.
I pay $10 at local Petsmart for the really good stuff 26" x 30" x 1/12."
This costs me about an average of 30 cents per monthly application in three filters. I think if you want the kind of crystal clear water that causes people almost faint when they see how stunning and polished your aquarium water is, you just have to bite the bullet. For $1 a month in two tanks ...... It's sure worth it to me. I also use Purigen in each my three Fluval C series filters.