TNB Naturals Enhancer CO2 Refill Pack Refill pack for the TNB Naturals Enhancer CO2 Dispersal Container! Up to 1200 ppm for a 12 x 12 x 12 grow space! Life span of 2+ weeks The TNB Enhancer CO2 Refill Pack gives growers the ability to reuse their existing Enhancer bottle while saving money and reducing their environmental footprint.