From: jimh@ultra.com (Jim Hurley)
Subject: Re: clogging sponge filters
Organization: Ultra Network Technologies
Date: Thu, 9 Apr 92 19:04:25 GMT

In <92Apr8.152521edt.309@smoke.cs.toronto.edu> enenkel@cs.toronto.edu (Robert Frederick Enenkel) writes:

[about clogged sponge filters]

>Robert Enenkel

My wife and I have been using the Tetra PHAS sponges, which certainly
look the same, for about a year with no problems. One is used
constantly as the sole filter on a 27g tank of assorted Tetras
and angelfish. The other is a spare that I keep running in various places,
usually the sump of my 100g tank.

She cleans it like you do, squeezing into a bucket of water from the tank.
She usually cleans it once a week.
The spare hasn't been cleaned in months, but doesn't get much crud.

Maybe it's clogging with algae or other sorts of wildlife?

A while back, J. DeRosa posted about the his experiences with sponge filters.
Since it's a pretty good article, I pasted it below.

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From rec.aquaria Fri Jan  3 13:20:00 1992
From: sonny@cbnewsf.cb.att.com (joseph.j.de rosa)
Newsgroups: rec.aquaria,alt.aquaria
Subject: Powerhead sponge filter
Organization: AT&T Bell Laboratories

In article <frazier.694462331@oahu> frazier@oahu.cs.ucla.edu (Greg Frazier) writes:
><ERSHC@CUNYVM.BITNET> writes:
>
>>Can a sponge be set up with a power head?
>Yes, they can.  There are some "power-sponge" filters which
>are sold with a powerhead (Eheim and Fluval both make these),
>but any good-sized sponge filter can be attached to a powerhed
>(We're currently using both a designed power-sponge and a homemade).

While it is true that a powerhead can be attached to a sponge filter designed
for air, I wouldn't reccomend it for a few reasons. First off, most of the
sponge filters that are sold are a very fine pore material. This clogs 
pretty quickly when run with an air pump, but even faster when powered by 
a powerhead. A powerhead will also make the gunk go pretty deep into the 
sponge, without too much hope of ever getting it out again. The sponge will 
begin to collapse on itself, and I think that the water runs through channels
in the sponge after a fairly short time (when used with a powerhead). 
The Tetra PHAS filters (Power Sponge Filters) have the same problem, although 
the sponge is larger, so it will take more time. 

I've used sponge filters for many years, with air and powerheads, and now I 
am convinced that the sponges that are sold have pores that are too small.
I have made a few sponge filters (from PVC, a powerhead of appropriate size, 
and an Large Aquaclear sponge (about $3.50), or a fluval sponge) and these 
work much better, and last much longer than the others. I don't think 
that these would be appropriate in a fry tank, or a tank with very small 
fish, but a powerhead would probably not be appropriate in these tanks anyway.
You COULD put a nylon stocking over the sponge to keep out fry and real tiny 
fish if you needed to, just make sure that there isn't too much water movement
for these fish.

The sponges mentioned (Fluval and Aquaclear) are coarse enough that they do 
not clog easily, and most of the gunk washes out. I have one that has not been
cleaned in over 3 months, and the flow has not diminished at all. 

There is one problem with these sponges, however, and that is making the hole.
I like to soak the sponge in water, then freeze it and use a drill to make 
the hole. I could also use a knife on a (thawed) sponge, but this is usually
pretty ragged.

>>stay clean, but now I see the sponge - heads say 'mechanical and
>>biological filtration should take place together'. Is this the current
>>consensus?
>
>Sounds like advertising hype.  After all, you *can't* separate
>the bio and mech filtration on a sponge - so why not claim that
>that is the best way to go? :-)
>Actually, there is the benefit that you will have lots of little
>thingies living in your sponge that fry enjoy, should your fish
>breed.

Just make sure that there isn't too much turbulance for fry.

Copyright 1991 jderosa@attmail.att.com All right s reserved  |J. DeRosa
Permission for reproduction in printed media or by           |AT&T  Room 1B32
Pay-for-read services explicityly disallowed. Permission     |100 Atrium Drive
is granted for reproduction by USENET & like free facilities |Somerset, NJ 08873

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Jim Hurley --> jimh@ultra.com  ...!ames!ultra!jimh  (408) 922-0100
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