I just got an EHEIM 2217 filter for my 90 gal tank but was checking the Eheim brand ceramic rings and media and boy that sh*t is expensive. Can I use ceramic ring from Ebay? http://www.ebay.com/itm/NEW-4-lbs-A...997162310?pt=Fish_Filters&hash=item2ecc5d4d46. Before I had some Fluvals (the olds 405) which are not bad but I'm thinking to do my own version of 2217 with a 6" diameter 36" long PVC pipe (The Eheim 2217 is about 8" diameter and 12" long) so I can put a large amount of media in it.