Scratching the surface of biowheels and bioballs

["S. Hieber" <shieber at yahoo_com>]

Back in the archives is a post from Roger S. Miller that says, in part,
about biowheels:
 
> I've always regarded them as a scam.  Harsh wording and all.  The
> problem isn't with the concept.  The problem is that the contact 
> surface on the biowheel and the contact time appear far too small
> to me.  The contact surface in an actual trickle filter is much,
> much larger.

> I don't use biowheels and never have, and I'm not saying they 
> don't work at all.  Lots of things work.  But, if you're in the
> market for an over-the-back power filter, then it looks to me
> like aquaclears pose fewer nuisance opportunities and provide
> more filter for the money. 

Allow me to speak purely from naivete -- I invite comments.  I have
always suspected that bioballs where something of a "scam."  They have
very little surface area per volume.  Porous materials like some kinds
of sintered glass or almost any shredded plastic have much more surface
area per volume.  Probably so do many fabrics, including the thin
material used in Biowheels.  But then, exposure to the air is a
critical element in the so-called wet/dry filtering process (which is
really a very silly name when you look at how any of these work).  So a
thick wad of felt perhaps would not be very effective because, even
though it would have a tremendous amount of surface are the core would
be oxygen "starved," relatively speaking.  Polyester batting (filter
floss) must fall somewhere between bioballs and felt, probably closer
to felt.

But if the idea is to get as much surface as possible into a volume
while ensuring plenty of air exposure, I can think of lots of things
better than bioballs and wonder why people buy them for use in
biofilters.


Scott H.

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