I am closing my new pool by myself this year after the builder helped me last year. We just blew air into the main drain line (pressurized), and then shut of the valve to trap the air in there. I bought a 6.5HP craftsman shop vac, but can't get enough pressure in there (assumuming it is because it is trying to blow into 8 feet of water), to blow air out. I am in ohio, thoughts? I hate to pay someone to come out to pressurize the one line every year! I have a small compressor also, but to pressurize more, I would need to rig up some sort of adaptor to screw onto the line, as just trying to hold it on there and make a seal isn't getting the job done with the vac or or the compressor.