12 Volt Man;3549081; said:
one thing that I think is important is that people often distinguish between 'mechanical' and 'biologcal' filtration as if they are seperate.
they aren't.
Weeeeeellll.... while I agree with everything you've said to qualify this statement, I would like to be a bit pedantic and state that many of us have a mechanical filtration device with minimal BB hosting potential, that we clean or swap out frequently, thus effectively keeping the BB colonies (for the most part) elsewhere.
Everything else you've put in though,



. Does your treatment facility include a denitrifying process as well? I'd like to pick your brain on that topic, but maybe that's a separate thread.
To add to the debate about whether BB grow effectively on glass vs a filter... maybe some of the effect comes from any dislodged, free floating BB getting drawn through the filter and over the media. This would give the bio media a much greater exposure to the water column AND to free floating bacteria, making it the preferred place to grow. However, as NC was alluding to, if you provide adequate food, O2 and flow in one location as well as the other, the bacteria will thrive equally. Supplying more than enough O2, food and flow, it won't make the bacteria multiply faster than their maximum - 9 men and a woman can't make a baby in a month, if ya know what I mean.
As for bio subbing as Mech - well yeah, and sponges are wonderful for that, as is filter floss, Jap matting and so on. I have a hard time believing bio balls and scrubbies would do any good in this regard however.