Originally Posted by
kimini
Take a moving-bed filter module, remove the diffuser, add a perforated plate and presto, a shower filter. Someone pointed out that at best, a moving-bed filter sees ~2% oxygen, but a shower can see 10x that because air is passing over it. Theoretically then, converting a moving-bed to a shower should make its efficiency increase by roughly 10x.
I know that K1-type media doesn't have the surface area like the media used in showers. The thing is, about every 10 years in this hobby everyone gets excited about the next great filter design that promises to cure everything, and it always includes a new media that has much higher surface area than current products. Remember when everyone used gravel? That worked great - for a while - until the bacteria plugged up the pores and killing its efficiency, and it was a PITA to clean because you couldn't clean out the internal pores. Remember lava rock? Same thing. Remember expanded clay? Same thing. So how does Cermedia/whatever sidestep this exact same clogging mechanism? I'm told that "if you feed it clean water it won't have a problem." Water coming out of a particulate filter is never perfectly clean, but the real problem is the natural cycling of the bacteria itself, that it can grow and live in microscopic pores, which is great, but when it dies, it dies in-place where the detritus can't be removed. The internal pores become packed with waste, reducing the surface area to no better than gravel over time, and while new media can be purchased it's very expensive. Obviously the life of Cermedia-type materials depends upon a lot of variables including number of fish, food loading, water turnover rate, type of particulate filter, etc, but it seems to me like plastic media is a functional middle ground where clogging won't be an issue.