The Pros and Cons of Rising Hardness Caused by Rocks

The charms of petrified wood are the unique textures and colors that are different from river rocks and mountain rocks. However, it tends to raise the hardness of water and makes it difficult to grow aquatic plants with it. The hardness of the water in the aquascape above reached 100 mg/l. Along with marine sand that was used for the substrate, it caused a typical, hard-water-related growth problem. Glossostigma not only failed to develop new leaves, it also became stunted and bleached. Although the use of Softenizer is effective for preventing the total hardness from rising, in this aquascape, I opted to reduce the water hardness by making water changes, using soft water that was prepared by soaking peat moss in it in a bear bottom tank. If aquatic plants tend to grow poorly in a layout with rocks, an increase in the hardness of water should be suspected. On the other hand, some fish display their original colors better in relatively hard water. Rummy Nose Rasbora (Sawbwa resplendens) is one of them. The water of their natural habit is slightly alkaline and its hardness is relatively high. This fish shows its characteristic colors well only when these water conditions are recreated. The problem here is how to strike a balance since the water quality favored by fish is different from the quality favored by aquatic plants. In the aquascape on the right, I used Aqua Soil Amazonia II for the substrate to maintain the slightly acidic and soft water that the aquatic plants prefer in the initial set-up period with the effect of the substrate material. As the aquatic plants cover the substrate surface, Ryuo-Seki turned the water slightly alkaline and raised the total hardness in turn, allowing the beautiful red color of Rummy Nose Rasbora to emerge from within. Selecting fish that favor hard water is a good option for an aquascape in which its water hardness tends to rise with the use of rocks.

Petrified Wood

Petrified wood is a fossilized wood. When CO2 is injected in the water where petrified wood is used, the calcium contained in the petrified wood leaches into the water and raises the total hardness of the water.

Rummy Nose Rasbora

This fish lives in Inle Lake in Myanmar. It favors slightly alkaline and somewhat hard water. The color of its body indicates whether the water quality is suitable for the fish or not.

Water quality data
Water temperature: 27°C; pH: 7.4; TH: 100 mg/ℓ; NH4: 0 mg/ℓ; NO2: <0.02 mg/ℓ; NO3: <1 mg/ℓ; COD: 4 mg/ℓ

Cichlids

Green Discus (Left and Second right), Golden angelfish (Second left), Scalare angelfish (Second right, Right).