sera Alder Cones 50 pcs – aquarium natural filter media for biological filtration

sera Alder Cones 50 pcs are natural alder cones supplied as a pack of fifty pieces for aquarium use. These cones serve as biologically active filter media that support colonization by beneficial bacteria, contribute to a gentle release of tannins, and help soften water and slightly lower pH. They are intended for freshwater aquaria, shrimp tanks and biotope setups where natural decor and subtle water conditioning are desired.

Advantages

The product is made from untreated natural alder cones, offering a stable porous surface for bacterial biofilm formation and gradual tannin leaching without synthetic additives. Because they are lightweight and compact, they can be placed inside filters, media bags or directly in the aquarium to provide long-term biological filtration support. Their neutral visual appearance also complements natural aquascapes and shrimp habitats.

Suitable for

• Freshwater community aquaria with soft to moderately hard water
• Shrimp tanks and planted tanks requiring gentle water conditioning
• Biotope and natural-style aquascapes that aim for tannin-stained water
• Internal or external filter compartments and media bags for biological filtration

When it may not be suitable

These alder cones gradually release tannins and can slightly lower pH and soften water; they may not be suitable for aquaria that require strictly neutral or hard, highly alkaline water parameters. Because they are natural materials, individual cones may vary in size and appearance and will change the water color mildly over time.

Key specifications

• Quantity per pack: 50 pieces
• Material: natural alder cones, untreated
• Application: biological filter media and natural decor
• Effects on water: gradual tannin release, mild softening, slight acidification
• Compatibility: freshwater aquaria, shrimp tanks, biotope setups

How to use

Rinse cones briefly with aquarium water or dechlorinated water before first use to remove loose debris. Place cones in filter compartments, media bags or directly on the substrate or hardscape. Monitor water parameters during initial weeks of use to assess tannin release and pH changes; remove some cones if staining or parameter shifts exceed desired values. Replace cones when they become overly degraded or if biological performance declines.

What to consider before purchase

• Intended water parameters: suitable for tanks where mild softening and tannin staining are acceptable
• Tank inhabitants: ensure shrimp and fish species tolerate reduced pH and tannin-stained water
• Placement options: measure filter or media bag space to confirm fit
• Visual effect: natural brown tinting of water over time

Usage recommendations

For steady biological support, distribute the alder cones between filter media and a separate media bag to balance water contact and reduce heavy staining. Start with a smaller number of cones and increase gradually while monitoring pH and water clarity to achieve the desired balance between biological activity and aesthetic effect.