Using non-SodaStream cylinders is not a good idea. All our CO2 cylinders are quality tested when refilled. SodaStream gas cylinders should only be maintained and refilled by SodaStream. Unauthorized refilling of cylinders by third parties could be risky. SodaStream only warrants the safety of cylinders refilled by us, and SodaStream is not responsible for products of any other company or brand, which may damage the Sparkling Water Maker and void the warranty.