This is the essay Takashi Amano wrote for his planted aquarium collection book Glass no Naka no Daishizen ( Nature Aquarium World ) published in 1992. It gives the opportunity to understand Amano’s unique views of nature and his experience.

Five Bottles of Carbonated Water

I decided to make a real effort raise water plants and design beautiful waterscapes in 1977. At that time there were no power filters and such devices like there are today, and figuring out my first set-up was difficult. I placed about 7cm of fine coral sand on the bottom and intensely aerated the water with a bottom filter. I thought that putting fishes in would cause problems, so I limited myself to plants. For lighting the 60cm tank I used two 20-watt bulbs: in a week the leaves were yellowing, and in two weeks they were transparent. There were no books to help me out. All I could do was grope on in the tank. Next I realized that while I could raise plants fairly successfully in old aquaria, the newer ones were just no good. While pondering the reason for this, I figured out that it wasn’t just air but CO₂ that they needed, so I asked my mentor, Professor Nagashima of Niigata Seiryo Women’s Junior College, about methods for carbonation of aquarium water. He told me that the 0.03% CO₂ in the air should be enough, and that it was naturally absorbed into the water so that I didn’t have to add it artificially. But he introduced me to a friend in the medical equipment field anyway, who discussed possible carbonation methods with me and gave me a cost estimate. It’s too bad it couldn’t have been done more inexpensively or I would have successfully set up an aquatic plant aquarium much sooner. Carbon dioxide was something I never needed in my work and it was too expensive a material for me, anyway. Dry ice was economical, but it was too hard to handle and disappeared too quickly to be practical. Frustrated, I went on struggling and tried to forget about CO₂. The aquatic plant aquarium work inched along to the point where the plants weren’t dying as much but they wouldn’t form new bubs. Then one night I went to a bar with a friend and a clear bottle of carbonated water caught my eye. The label said, “water, carbon dioxide, sodium, chloride (NaCl) 1%.” I wasn’t sure about the NaCl but it was the perfect material for testing whether the plants needed CO₂. I took five bottles home with me. The tank for the experiment was big: 240×60×60cm. Flushed with drink and excitement, I poured the five bottles in. Within five minutes air bubbles had formed on the leaves: they did need the CO₂. Every tank I added the soda water to did well, but I had to be careful not to add too much because of that 1% NaCl, and so I changed the water faithfully every week. There were piles of empty soda water bottles all over my room. If I hadn’t discovered that carbonated water when I did, I surely would have given up on the whole idea of aquatic plant aquaria.

Nature Aquarium World (TFH, 1992)