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From: bc@mit-amt.UUCP
Newsgroups: alt.aquaria
Subject: Re: Fishtank Moved
Message-ID: <1755@mit-amt.MEDIA.MIT.EDU>
Date: Thu, 19-Nov-87 12:54:10 EST
Article-I.D.: mit-amt.1755
Posted: Thu Nov 19 12:54:10 1987
Date-Received: Sat, 21-Nov-87 16:29:32 EST
References: <1753@mit-amt.MEDIA.MIT.EDU> <4370@sol.ARPA>
Reply-To: bc@media-lab.MEDIA.MIT.EDU (bill coderre)
Organization: MIT Media Lab, Cambridge MA
Lines: 29

In article <4370@sol.ARPA> becker@cs.rochester.edu (Tim Becker) writes:
>What's diatomaceous earth filtration?  Sounds real nice to be able to
>clear out all the "junk" you mentioned in a couple of hours...

Diatoms are Bacillariophyta (flip flip, turn pages) (ahem):

Leeetle Leetle algae, single-cell or colonizing. The capsules of the
algae have extremely fine intricate structures.

Anyway, they are small enough that if you take a pile of dead ones
(looks like a fine white powder), and incorporate them into a matrix,
you can filter things out on the micron scale. Like rust particles.

Swimming pools are often filtered this way.

Lots of aquarium filters can use a diatomaceous earth attachment,
usually a paper filter that you then pour a suspension of dead diatoms
into. The diatoms stick to the paper, and then they filter the water.

Eheim filters can take both diatom and carbon filter packs. Usually,
what one does is run a diatom charge for a few hours, then switch to
carbon. Eheim claims the paper filter alone is pretty good. Well, I
dunno about that.

There are also entirely diatom-based filters.

It's my guess that a diatom filter doesn't build up as much of a
bacteria base (lower surface area) as a carbon filter, so that's why I
use both............................................................bc