Aquarium Gravel Sera Gravel Dark Coarse 3–6 mm 10 kg

Sera Gravel Dark Coarse 3–6 mm is a dark-coloured aquarium substrate supplied in a 10 kg bag, intended for use in both freshwater and marine tanks. The coarse grain fraction between 3 and 6 mm creates a stable base layer that supports plant roots and provides ample surface area for beneficial bacteria, while contributing to a natural-looking aquarium landscape. Its dark tone enhances contrast with aquatic plants and fish, helping colours stand out without altering water chemistry when used according to manufacturer guidelines.

Advantages

The coarse 3–6 mm grain size ensures good water circulation through the substrate and reduces compaction compared with finer sands, which helps maintain aerobic zones for root systems and nitrifying bacteria. The dark colour provides visual depth and contrast that highlights plant growth and fish coloration. Supplied in a 10 kg unit, the gravel is suitable for creating an even, stable layer across typical home and display aquaria and supports aquascaping, planting and breeding setups.

Suitable for

• Freshwater planted aquaria where a stable coarse substrate is required
• Marine and brackish tanks looking for a dark decorative base
• Breeding tanks and shelters where a stable bottom layer is beneficial
• General tank landscaping and aquascaping projects

Key specifications

• Grain size: 3–6 mm
• Colour: dark / deep tone
• Net weight: 10 kg
• Suitable for freshwater and marine aquaria
• Designed to support plant roots and biological filtration
• Coarse fraction reduces compaction and improves circulation

How to use

Rinse gravel thoroughly with water before adding it to the aquarium to remove dust and fines. Spread an even layer 2–5 cm deep for general use; increase depth in planted tanks where root anchoring is required. Place plants, decorations and hardscape on top of the prepared substrate. When performing maintenance, siphon detritus from the surface without disturbing the entire layer to preserve bacterial colonies and root systems.

Usage recommendations

For planted aquaria, combine with a nutrient layer or root fertiliser below the gravel if intensive plant growth is intended. Avoid using acidic cleaning agents; only rinse with plain water. Monitor water parameters after initial setup and after extensive cleaning to ensure stability.