Re: No Filter Planted Tank

>From: "Williams, Rochelle - DCSPIM" <williaro at ftmcphsn-emh1_army.mil>
>Date: Tue, 31 Dec 1996 13:24:00 -0500
>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?

I cut the rest of the post, but it does describe detail that I may mention.

I have a 5.5g zero forced water movement tank at my office.  This tank has two
fish in it (small platies) and a few snails.  I feed twice a week with flake

The platies do not seem to have a problem with low oxygen levels in the water,
but I keep the water shallow.  The deepest it has been is about 3", and it's
currently 2" deep.   To-date, I haven't changed the water at all (1.5 yrs), and
the plants and fish seem to be healthy.  Eveporation is kept to a bare minimum
with a loose-fitting cellophane cover on the tank.

My plants are Java Fern, H. difformis, Java Moss, and Duckweed.  They all do
well, and the duckweed can be used as an indicator of water quality (more
duckweed = lower quality).  All of my plants are mostly emersed, giving them
ready access to CO2, plus significantly more light than they would have if they
were submersed in this tank with my single 15w tube.

Unless you're planning on keeping air-breathing fish, I would find some way to
turn the water over in the tank.  I'm not convinced that Brownian motion is
enough, and 15w suspended 6" above the tank won't stimulate the plants to
enough photosynthesis to keep several fish happy, IMO.

I hope this helps, and Happy New Year!

David Webb in extremely foggy Dallas Texas