Everyone here has an opinion, so heck, I'll weigh in. I think both sides of the issue have valid points and the truth lies somewhere in the middle
. Water flow is important and
overall surface area is important. I do believe that the porous ceramic media will become "clogged" over time. Other than profit-margin, that's why manufacturers of ceramic/glass media recommend scheduled replacement of the media. Having said that, I think the bio-ceramic media, with the larger surface area for bacterial attachment is very effective and in my opinion
(I personally don't have data to support) more effective than "smooth" media like the twisted plastic shavings used in some wet/dry filters. Now, long-term, the bio-ceramic's probably less cost-effective in terms of replacement frequency!
Ok, now to some biology to support my opinion. Fact: some bacteria have the ability to form biofilms, bacteria grow, reproduce, die, and bacteria attach to substrates. Now, all that dead bacteria doesn't necessarily 100% disappear, and that "detritus", along with any biofilms secreted will certainly clog up porous media over time. So can microscopic "crud" in the water. Granted, not all bacteria secrete biofilms, but our aquaria are not sterile environments either and have many bacteria types. Biofilms are notoriously resistant to chemical removal (hard to remove even mechanically). That's why your dental hygienist spends so much time scraping teeth during your visit - biofilm!
Water flow over the surface is not the entire issue either. While water flows across the media, smooth or porous, it brings oxygen, allowing greater bacterial activity. While water flows across the ceramic media, oxygen and waste products diffuse into the cracks, creases, and pores of the bio-media. The added surface area for bacterial attachment means there's a lot
more surface area for bacterial growth in the porous media system. It's the same idea as our intestinal villi (small projections and valleys in our intestines to increase surface area for food absorption). This surface area makes the bio-media much more effective at holding larger quantities of bacteria and processing waste products but only as long as it's not clogged up
IMO, cleaning porous media may help a little, but it certainly won't restore it to 100% function. Regarding Seachem's matrix? Forever is a long time and as they say "nothing lasts forever"!
What's best? Use what works and what you like. We all get attached to certain things, they each have pros and cons.