Pond Boss Forums AERATION Systems questions Check Valve Advice and Questions

I have a small rotary vein compressor attached to an old style air pod diffuser by way of 3/8" heavy set tubing. My problem is that I can't close the relief valve all the way during startup because the back pressure is too high for my pump. I would like to pump as much air as my compressor can handle, but its just not possible unless I'm there to manually control the relief valve until the pressure stabilizes.

What type of inline checkvalve do you recommend I use? Also, does it matter where the checkvalve is attached to the line? Does it have to be near the diffuser or can it be attached near the compressor? Sorry for my ignorance with this aeration stuff.