Water Chemistry
Target Parameters
| Parameter | Koi | Goldfish |
|---|---|---|
| pH | 7.0 – 8.5 | 7.0 – 8.0 |
| GH | 8–20 °dGH | 8–20 °dGH |
| KH | 5–12 °dKH | 4–10 °dKH |
| NH₃ | 0 | 0 |
| NO₂ | 0 | 0 |
| NO₃ | < 50 ppm | < 50 ppm |
| Temperature | 4 – 30°C (optimal 18–24°C) | 4 – 28°C (optimal 15–22°C) |
| Dissolved O₂ | > 7 mg/L | > 7 mg/L |
Differences from an indoor aquarium
- The temperature varies seasonally—the fish adapt
- Large volumes = greater chemical stability
- Acid rain can lower the pH in ponds without a buffer
- Evaporation in the summer concentrates the minerals—add high-quality water to compensate
- Plants play a key role in biological filtration
- KH is especially important for pH buffering—maintain a level > 5 °dKH
Essential Tests for Ponds
- Spring (when the fish wake up): NH₃, NO₂, NO₃, pH
- Weekly during the active season: NH₃, NO₂
- Monthly: pH, KH, GH, NO₃
- After Each Death: A Comprehensive Analysis