Alder cones to reduce pH value naturally Sera alder cones prevent fungal infections and naturally cause fungus. In addition, they support natural behavior and spawning readiness, and they lower the pH value of the water. Alder cones are suitable for the preparation of black water, which reproduces natural living conditions and allows appropriate care Application 1 cone per each 10 l (2.6 US gal.) of aquarium water can be added. Dosage can be up to 1 cone per 1 l (1 US quart) for supporting disease treatments. However, the pH value needs to be monitored when doing so.