I am going to be running a fuel cell with 2 fass pumps. So I will have 2 lift pumps returning fuel and 2 injection pump returning fuel. The fuel cell only has 2 return/vent ports on the top and I wanted to know if a vented cap was enough to vent the tank or it I need to have a vent also. I figured there would be too much fuel returning for just one -10 AN fitting to accept all of it.