Fluval BIO-CO2 Refill Pack The Fluval Bio-CO2 Pro Refill Pack has been designed for use with the Fluval Bio-CO2 Pro Systems for maximum CO2 production. The Refill Pack is required to kickstart the biological fermentation process in the Fluval BIO-CO2 reaction chambers. The professionally crafted activator yeast sachets are used in combination with the booster tablets to rapidly jump-start the fermentation process and start CO2 production within 24 hours. The Bio-CO2 Pro Refill Packs are supplied in air-tight, aluminium-lined sachets for consistent quality and storage for up to 2 years. Each Fluval Bio-CO2 Pro Refill Pack includes: 4 x Activator Yeast Sachets 4 x Booster Tablets Suitable for use with the Fluval Bio-CO2 Pro 125L & 250L 4 x Activator yeast sachets & Boost Tablets per pack Produces CO2 within 24 hours Convenient & easy to use Long lasting - Up to 30 days per refill Safe biological process Sustainable - Environmentally friendly Essential for plant growth, colour and health