This page is devoted to the design of the asellus filter. Basically - how do you build your own.
This image was generated by members of nissikigoi-bassin.
It is the "classic" asellus filter that they designed and have been successful with.
Mine is a varient of theirs. I have added the English translations.
Above is the over all big picture - building a copy of this would be a complete koi pond filter. Of course a protien skimmer, tricle towers, Ozone, and etc... could also be used. But what if you already have a system and just want to augment it or add an organic particle filter. What I want to explain on this page is how basic particle filters work and how asellus does it's job.
If you look at chamber 1 (K1 Kaldness static) you'll see that the water needs to work its way past all the media floating in the upflow water column. Each time the suspended particles bump the media or change direction they have a chance to stick to the media. This is what cleans the water of particles.
If that's all you did the media would fill with debris and foul, with too much debris, it would cut off the air supply and go anerobic (very bad). This is where the asellus come in - with a large enough population the asellus eat the debris (both decaying animal and plant) and keep the media clean.
Asellus biology:
Details off the top of my head - if you find better data, go with it.
Name: Asellus Aquaticus (as far as I have been able to find)
Lifespan: 4-6 months
Size: 5/8 th of an inch max.
Details/trivia: Isopod crustation. Females molts posterior half of exoskeleton making them available
for mating. Males stradle the female (probably prior to posterior molt), mate, and hold female under
the male until the female molts the anterior half, making them incapable of further fertalization.
Females grow egg case under legs and apparently have a pouch for babies when they hatch.
Reproductive rate: I don't know, but my population more than doubled in two months from mid March to
mid May.
Here is how I would build a chamber to grow out asellus (increasing their population to make them usefull for filtration purposes).
