Re: Plant Filtration

>From: Stan Perkins <sperkins at admin4_hsc.uth.tmc.edu>
>Date: Fri, 1 Dec 95 16:51:44 -0600
>Subject: Pond filter

>Some time back I remember reading of an interesting filter application 
>for ponds.  One component of this filter consisted of a tray(s) of 
>aquatic plants such as water hyacinth or water lettuce whose roots acted 
>as a biological filter media. If someone, with a mind less cluttered than 
>mine, could please send details of the construction of the filter.  I 
>have a friend interested in adding something like this to his pond setup. 

I use this sort of filter in my fishroom.  The system contains about 400g
and the filters are two 6'x 2' x 1' containers divided into three 2' x 2'
sections.  The water drains into section 1 and exits at sections 3.  Sections 1-2 are lit by 80w flourestent fixtures.  Section 1 grows hornwort
and sections 2 amazon frog bit and duckweed.  The water comming out of 
the filter is quite clean - except when I clean the filters.  I am going to
add an filtration stage after the pump to catch the crud that manages to
get through the filters.

Problems.  If you get bad algae it will slowly spread into all your tanks (any central system has this problem).  If you are not efficient at collecting crud you make end up with blue/green algae (two 14 tanks have
this problem now - they are the first two the filtered water gets to).
You must regularly thin the plants - every two weeks is ideal, once a 
month is ok but more work (summer is not fish time).


Ed Tomlinson (tomlins at cam_org)
Montreal, Canada

Home of pppdial: http://www.cam.org/~tomlins/pppdial.html