Is the "mulm" good or bad, and why?
It is if it blocks oxygen from getting to the bacteria as in between the plates of an RBC and anaerobic bacteria takes over. The bacteria you want is aerobic and is used to break down ammonia and nitrites. (To be covered later.) It can also plug drains and waterlines.
[quote=fish n chips]Not that important, but any Pics of mulm?
No but should have taken a picture a couple of days ago of some mulm that was blocking a vinyl water line from my clarifier filter to my moving bed filter.
