Key Features Highly porous, biological media for all types of aquarium filter. Quartz like material can help eliminate harmful toxins like nitrate and ammonia. Large Surface Area for beneficial bacteria. 500g Box - 5-10mm Beads Pack of 1 (500g) Creates a large surface area for the ‘beneficial’ bacteria to colonise, increasing the break down of harmful Nitrates and Nitrites producing better quality water for your fish. Highly porous, biological media for all types of aquarium filter. 500g box Each bio bead is approximately 5-10mm in diameter
