I have a friend who has just finished his basement. He had a upflush toilet installed and has been having some problems with it. The first was some water hammer as the water flowed back against the check valve. His plumber suggested installing a second check valve(?) and a verticle pipe to act as an air chamber. I have limited knowlege of plumbing but these dont sound like the best of solutions. The air chamber on the waste pipe seems alittle shadey and the second check valve seems it would only reduce the water hammer on the first check valve if it was installed quite a bit further up on the waste pipe. The second more serious problem is that the toliet has a very weak flush that renders it all but unusable. If he uses the sink in the bathroom, the lift pump turns on and sucks all the water out of his toilet. It sounded to me like he had at the very least a venting problem. I have not seen his set-up but he says the venting system is mechanical and doesn't actually vent to the outside. I have never heard or seen this type of vent (he said it was a Suttor Vent...unsure about the spelling). Any input you guys have would be greatly appreciated.