Since installing a new CO2 system I've tore thru 2 2kg bottles of CO2 in around 3 weeks. I've checked the system for leaks using washing up liquid and water and can't seem to find anything. I've even checked the valves inside my PH controller. When I removed the CO2 lines from the pressure reducer water came out. Checked the non return valve, and when I blow thru it there seems to be a fair amount of resistance to allow air to pass. And yes, I'm blowing the right way . I'm thinking the resistance may be causing pressure build up elsewhere in the system and causing the leak. Should there even be resistance?