Path: utzoo!hoptoad!ihnp4!homxb!agd
From: agd@homxb.UUCP (A.DEACON)
Newsgroups: alt.aquaria
Subject: Re: question about biological filtration
Message-ID: <1264@homxb.UUCP>
Date: 21 Dec 87 20:39:18 GMT
References: <193@bacchus.DEC.COM>
Organization: AT&T Bell Laboratories, Holmdel
Lines: 31
Summary: You're right.

In article <193@bacchus.DEC.COM>, reid@decwrl.dec.com (Brian Reid) writes:
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> I am puzzled why it is not possible to set up outboard gravel filters. It
> seems to me that as long as the water flows through bacteria colonies in the
> gravel, it shouldn't matter whether the gravel is at the bottom of the tank
> or off in another room. Why couldn't you have a circulating pump that drew
> water out of the marine tank, pumped it through a large bank of gravel beds
> that was kept nearby, and then pumped it back into the aquarium?
> 
> Perhaps the answer is that there are other substances that are more efficient
> than gravel when used outboard, such as polyester floss. Perhaps these
> "Bio-balls" things, that I read about but don't quite comprehend, are a
> gravel substitute for forming bacteria colonies on outboard filters.
> Can somebody enlighten me? I would guess that posting your answer would be
> better than mailing it, because I can't imagine I'm the only one who wonders
> about these things.
> 
> Brian Reid

This is the principle behind the wet/dry and trickle filters
that have been discussed here recently.  Bio-Balls happen to
be the media produced by Dupla to accomplish the "gravel"
part of the system.  The system provides oxygen saturation
and improved filter volume/ tank volume to allow for higher
tank populations than with other filter concepts.

Art Deacon