Re: Aquatic Plants Digest V2 #419

>From: "Williams, Rochelle - DCSPIM" <williaro at ftmcphsn-emh1_army.mil>
>Date: Tue, 31 Dec 1996 13:24:00 -0500
>Subject: No Filter Planted Tank
>I'm trying a no filter tank in the office and wonder if there is a
>specific FAQ or book recommended for general information.  Specifically,
>how does water circulation work in these tanks?  If the plants use up
>the available nutrients in the water that is touching them, how does the
>water move to provide a continuous supply?  Is Brownian motion enough?
>Specifics are 3gal hex, open top, acrylic tank using fine gravel with
>peat/soil/clay mix taken from previous tank.  Fertilizer tablets were
>added at the recommended rate (Tetra Crypto Dunger) and was planted with
>4 pygmy chain swords, 3 anubias nana, a  very small red rubin sword, 2
>aquatic shamrocks  and 4 stems of moneywart (??) (I forget the correct
>names of these last two).  Lighting is a 15watt florescent suspended
>about 6" above the tank.   Inhabitants include a 1" apple snail,
>multiple Malaysian Trumpet snails, and I plan to add a betta or paradise
>fish.  There will be weekly water changes but no filter, heater or air
>stone.  Office temps are in the 70s, light is on a timer.

Diffusion is the movement of some substance from a higher concentration to
a lower concentration. It occurs because of the random molecular motion of
the substance and of the water.   In totally motionless water, diffusion of
relatively small molecular weight substances, such as dissolved mineral
nutrients, can go several inches in a week.  However, in any tank the water
will be moving and mixing because of temperature fluctuations in the room
and the motions of the fish.  Also the plants move water from the roots
through the leaves.  As long as you don't exceed roughly 1 inch of fish per
gallon (small fish), everything should be fine with no aeration or
filtration. Bettas like 80 degrees, but paradise fish don't mind a cool

Paul Krombholz                  Tougaloo College, Tougaloo, MS  39174
In warm, foggy Jackson, Mississippi.