That Gasp pump is no where near powerful enough to work the HF venturi... To use the HF Venturi you need an air compressor not an air pump.
If you attach the hose to the input connection of the pump it will work as a vacuum pump... it is not really recommended and will not draw as much vacuum as a true vacuum pump, but a lot of woodturners are using that system to hold bowls in place on the lathe... so it must pump enough.
HOWEVER, it is not meant for long term holding of vacuum... when you get the vacuum you need, close off the line and shut off the pump... you don't want to burn out the motor.
ALSO, those pumps work real well with air brushes for applying lacquer finish.