needlewheel venturi?

[JB]

I bought a Gen X 2400 needlewheel pump for a small recirculating skimmer I am building. Curious about the air intake/venturi for a needlewheel pump. Do I really need a venturi with a needlewheel pump, or just an air line near the intake of the pump? I havent put the pump in water yet, so im not sure on how hard the pump will push water, but venturi are not very efficient without decent velocity of the water going through the venturi, right? The fitting that came with the pump, isn't very "venturi" looking(or threaded on both ends), that is what made me curious if i need a venturi at all. Also, how far below the water line, in the skimmer tube, would you put the intake pipe? Guessing as close to the top as possible with out sucking out foam?
Thanks Jason

 

[H20ENG]

I made a "venturi" for a Genx 2400. Its in my gallery. Basically used a 1" fitting, and tapped in a Speedfit. I drilled out the Speedfit fitting stop and pushed the tubing all the way through. The tubing itself creates enough flow restriction to get the venturi effect. I used 3/8 tubing to get more air in. I sliced the tubing at a steep angle to get more open area exposed to the impeller.
Works great. I have had one GenX break from running dry (low sump, not from drawing air), so be careful.
HTH,
Chris

 

[H20ENG]

Here you go.

And here is the skimmer its on- a dual injected AND needlewheel beast

 

[JB]

Thanks H20ENG,
I will try that, pretty simple, and cheap to change if i need.
Jason