Eheim SUBSTRATpro+ O2xygen Biological Filter Media 250ml (2512001) The Eheim SUBSTRATpro+ O2xygen is a next-generation biological filter media that revolutionises biological water treatment in freshwater and marine aquariums. Built on the foundation of the trusted and proven Eheim SUBSTRATpro, this latest development combines sintered glass spheres with the gemstone mineral tourmaline — delivering a breakthrough in biological filtration performance. The secret behind the extraordinary effect of SUBSTRATpro+ O2xygen lies in tourmaline's unique pyroelectric properties. On contact with water, tourmaline generates electron-activated oxygen (super oxygen O2-) — optimising the oxygen supply within the filter substrate and creating ideal conditions for beneficial filter bacteria to colonise, thrive, and break down harmful pollutants faster and more efficiently than standard biological media. The 250ml pack (183g) is the ideal entry-size for smaller internal and external filters, nano aquariums, and topping up existing filter media. It is also the recommended size for use in Eheim Aquaball and BioPower internal filters. Key Features Tourmaline-enhanced formula: Contains the gemstone mineral tourmaline which generates electron-activated oxygen (O2-) on contact with water — optimising oxygen supply and creating ideal conditions for beneficial bacteria 45% porosity: High-porosity sintered glass spheres provide an enormous internal surface area for maximum beneficial bacteria colonisation Spherical shape: Allows high packing density in the filter chamber while ensuring optimal water flow through the media — maximises use of available filter space Fast pollutant breakdown: Activated oxygen accelerates metabolic processes in the filter, resulting in faster and more efficient removal of harmful substances including ammonia and nitrite Promotes aquarium vitality: Activated oxygen strengthens fish, plants, and the entire aquatic ecosystem — not just filtration performance pH-neutral: Does not affect water chemistry — safe for freshwater and marine aquariums Durable and long-lasting: Fired at over 1000°C — material is exceptionally robust and resistant to breakdown Reusable: Rinse carefully in old aquarium water during maintenance and reuse — do not clean in tap water Recommended for Eheim Aquaball and BioPower: The 250ml size is specifically recommended for use in these Eheim internal filter models Compatible with all Eheim filters: Suitable for external canister filters, sumps, Aquaball, BioPower, and other internal filters Compatibility Suitable for: All Eheim external canister filters, Aquaball, BioPower, sumps, and compatible internal filters Water type: Freshwater and marine aquariums Pack size: 250ml / 183g Product Details Brand: Eheim Product Code: 2512001 Type: Biological Filter Media Material: Sintered glass with tourmaline mineral Porosity: 45% Volume: 250ml Weight: 183g pH: Neutral Suitable For: Freshwater and marine aquariums Maintenance tip: Replace approximately half of the media every 6–12 months to preserve bacterial colony stability. Always rinse in old aquarium water — never tap water — to protect the beneficial bacteria that have colonised the media. The Eheim SUBSTRATpro+ O2xygen 250ml is ideal for aquarium keepers running smaller internal or external filters, nano tanks, or anyone wanting to trial the SUBSTRATpro+ O2xygen technology before committing to a larger volume.
