This month we are proud to present Diana Walstad's low-tech aquarium. She is the author of
Ecology of the Planted Aquarium and has a great impact on our hobby, especially for those who go El Natural. Let's enjoy her style.
Introduction and Background: 
I come from a family that always had tanks in the house and a pond in the backyard. I never had any luck with aquarium plants until I started using a soil underlayer in the tanks. Plant growth was phenomenal
- like nothing I had seen before. With the robust plant growth, I found that I could keep fish healthy without a lot of tedious work (water changes, gravel cleaning, etc). I began combing the scientific literature for more information and started writing articles for the Aquatic Gardener Association. One thing led to another. I first published Ecology of the Planted Aquarium in 1999. The book has done well. It has been translated into German and Italian and is now available as an e-book.
I trained in microbiology and spent many years doing medical research. I work now as a cell biologist for the federal government.
The Tank:
I set up this 45 gal (170 liters) in 2001. I had problems with green water algae and mat algae the first year. However, plants always did well in it. Eventually it became my favorite tank.
Tank dimensions are (48 X 13 X 18). Tank is next to a large window with a sunny Western exposure.
Lighting: two 40-watt T-12 bulbs in a dual strip-light fitted with an aluminum reflector. One bulb is a cool-white; the other is an Aquarium Plant Bulb (pinkish color). Tank gets muted sunlight (slatted blinds drawn across window to reduce sunlight intensity and cut down on algae)
CO2 system: No artificial system. Fish respiration and bacterial decomposition of organic matter provide CO2 naturally.
Substrate: I layered the bare bottom with 16 lb of an inexpensive potting soil designed for growing houseplants. Layer was about 1 inch (2.5 cm) deep. The manufacturer listed the following ingredients: Organic compost from mushrooms and other materials, peat humus, sand and bark fines, vermiculite, perlite, and dolomitic limestone. I mixed 2 tablespoons of phosphate fertilizer with the potting soil. Then I covered the gravel with 25 lb of medium-size gravel.
Hardscape: None
Filtration: Submerged Powerhead (AquaClear 301) with an attached Quick filter.
Maintenance: I change about 50% of the water every 3-6 months. I clean the filter cartridge, trim plants and remove mat algae about every month.
Inhabitants: Twelve Rainbowfish. Ramshorn and Malaysian Trumpet Snails.
Fish feeding: Twice day with mostly flake food or dried bloodworms. Fish get treats like chopped chicken liver or hard-boiled egg yolk once a week.
Plant fertilization: None.
Water Parameters (approximate): Ammonia = 0. Nitrite = 0. Nitrates = 5-10 ppm. GH = 8. pH = 7.4 (late morning). Specific Conductance = 250 microSiemens/cm.
Aquascaping: I planted tall, strap-leafed plants (
Cryptocoryne balansae,
Sagittaria graminea,
C. wendtii, and a single
Echinodorus major) on one end of the tank. I put
Anubias nana and .
Rotala indica on the other end. Small plants (
Echinodorus tenellus and
Sagitarria subulata) went in the center.
Cryptocoryne cordata blassii began to propagate well enough that I let it become a central focus for the tank. Initially, I planted many other species, but these are the plants that survived. Most of the trimming/plant removal is designed to keep
C. balansae and
R. indica from taking over the tank.
This picture shows me and the film crew of NOVA NOW, the science show on the USA's PBS (PublicBroadcasting Station). They came last year to take pictures of my tanks. This picture includes the 45 gal tank I wrote about, me (blue shirt and white slacks), and some of the NOVA film crew.
February 2007 Tank of the Month: Diana Walstad 
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