I'm not sure if you get the same level micron filtration by doing this...but stuffing some 100% polyester filling into a sock and using that has been just as effective for me. Not to mention you can get a TON of it at Michael's or wherever for $5.
So summary:
Cheapo filter sock: $2-3
Poly Filling: $5
So: $8 for around 50 refills.
Poly filters are chemical not mechanical filters.


