I'm also intrigued by this same question! I have always bought into the "hype" of brand name bio-media (Seachem Matrix) and have found that it has done its job as expected. But when I read the website that @Somefishguy
linked above, I wondered whether pot scrubbers, foam or the K1 extruded plastic could be just as good, if not better. I came across some K1 media on sale recently so bought a couple of bags to take a look at and maybe see about trying to replace existing Matrix with it in a canister filter (given that the article says it should be more than 4x better than Matrix!).
I asked here if anyone had used K1 as static media (i.e. not in a moving bed setup), but so far zero replies:
Anyone us K1 as static media in a canister?
I know that people do use pot scrubbers and foam as their only biomedia, but I wonder how common this actually is.
In short, if foam, pot scrubbers and K1 media are soooo much better, than why aren't we all using them?
Really interested in hearing personal experience from the many experienced (dare I say expert?) people on this forum!
So what do people actually think - are these cheaper alterantives actually so much better than the commercial bio-medias????