Re: No Filter Planted Tank

> 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.

I've used filterless tanks for rearing Bettas successfully. I
think you could use sunlight but you need to make sure that
the room temperature is warm enough so that the tank stays
above 72F or so. My room temps run about 75F with 500 watts of
MH lights keeping things nice and warm most of the time.
I use the 15 watt compact fluorescent fixtures over a 2 gal 
tank. Once the males get large enough to start scrapping, 
they've got to be relocated. Once you take out the dominant 
male expect a power struggle. With Bettas, I used Salvinia 
and Ceratopteris. I tried it with some Killies but have better 
luck using Elodea and Cabomba and a little Ceratopteris. I don't 
think Salvinia puts oxygen in the water and it covers too much 
surface and this prevents oxygen from diffusing into the water 
from the air. Both Elodea and Cabomba grow well without any 
substrate under my conditions. I haven't added any micro nutrients 
yet but the plants were grown in larger tanks and may have
stored Fe and other nutrients in excess for later growth.
These plants have only grown this way for a couple months
but no symptoms of deficiency that I can tell. I don't really
know if you can keep Bettas at temps lower than 72 because
that's as low as I go. I suspect they can go lower. A
glass top would cut down on evaporation but it would cut
down on oxygen too. A small tank is tricky but Bettas
are the best fish to use I think. I also use snails to
take care of uneaten food which can rapidly poison the
water. I have no substrate so I suck detritus up with a
baster. It doesn't work well with peat however.