Takahito Mizuno
Nine years have passed since the creation of the “Natural Aquascape” in the Sumida Aquarium, which was considered as the world’s largest Nature Aquarium at the time. We will share a series of behind-the-scenes stories about its creation and maintenance, which has not been talked about much until now.

Water quality management for the Natural Aquascape

In many areas of Japan, we have soft tap water with a pH level around 7 and a total hardness (TH) about 50mg/L, which makes it relatively easy to grow aquatic plants. And especially if Aqua Soil-Amazonia is used as substrate, plants would most likely grow smoothly without adding much water conditioners other than Chlor-Off. In reality however, the quality of tap water fluctuates greatly depending on the time of year. At the Sumida Aquarium, the total hardness of tap water can be as high as around 100 mg/L. If you continue to perform water changes without noticing it, the buffering effect of Aqua Soil-Amazonia alone won’t be enough to control the rise in TH, and as a result the growth of aquatic plants might be hampered. We run water quality tests in all the Natural Aquascape tanks once a week to avoid risks caused by water quality fluctuations. It is a steady process, but it helps us understand some trends from the data collected over the years, and use it as a guide for the application of liquid fertilizers and the use of cation filter according to the variables of water quality. We use NA Water at each water change even when a cation filter is not necessary because although tap water looks clear, it may contain water scale and rust.
NA Water
In the Natural Aquascape where a large amount of water is used, filter cartridges will clog up quickly. If dirty cartridges are kept in use, they will negatively affect the quality of the tanks due to their reduced performance. It is important to monitor the quality of your aquarium water on a regular basis because maintaining stable water quality is the first step to growing healthy aquatic plants.
Water scale can build up so much in a few days.