I think ptfe tape is fine. I cant see why they would say its not alright. Use and double check by pouring or spraying soapy water at the joint.Can someone help me cos I realy have a leak and I don't now how to fix it properly. I have regulator from co2art and bottle from aquamedic. I watched tutorial on co2art page and they say if leak use ptfe tape. Is it safe to use it inbetween regulator and bottle cos I read somewhere that it is not good?i also put rubber o ring in there and it still has a leak