Pump modification?

[Boo Boo]

I've got a Boyd slide in unit (100 fresh 300 waste) with a vacuum only pump. I'd like to route the exhaust from the pump back into the tank to pressureize the tank as some of the waste stays in the tank even though the front of the truck is up on ramps. Anyone else done this?

[pshed]

if you have a vacum pump, putting the exhaust into the tank will NOT pressureize tank, you'll be circulating the air thats it, you need 4 way valve on your pump