Negative head height with venturi power head -question

[CMuentener]

I know that pump head height is normally thought of pushing water up vertically. My question is do the same calculation/precautions apply if you pump is below the main volume of water.   I'm looking at setting up a new reef tank with the sump located in the basement below the display tank.  I'll be using a CPR overflow box and a verturi powerhead to keep air out of the overflow box.  The sump tank will be about 12 feet below the display tank.  Can I place the powerhead connected to the overflow box in my sump and run an air line to the overflow box or should I hide the powerhead in the display tank?

 

Thanks 

 

[patback]

I'm confused.  Are you able to draw up a quick pic of what you are proposing to do?  

[CMuentener]

I want to hook up a power head w/ a Venturi connection to my cpr overflow box. In order to remove any potentially trapped air.  Didn’t know if I should keep power head in the DT or can I put power head in sump tank(in the basement) see pic. Thank you