There is an aqua-medic distributor in Leigh. And he can get you a cheaper regulator with integrated needle valve, bubble counter, and a 350g cylinder for $323. His name is Barry Torkington. The problem with him is half the time he is in US but he is a very nice guy. Check out the website www.aqua-medic.de look him up under dealers section. He is still in America at the moment and should return in 2-3 weeks time. By the way what kind of gravel do you use in you planted tank.
Hope this help