Baitwell pump
 

Im building a new baitwell and id like to have a thuhull scoop for waterflow running with the pump off. Ive had them on past boats bUt never plumbed one.
With theese pumps
http://www.wholesalemarine.com/mm5/g...4640-7_med.jpg
shy the long threaded pipe and nut what is it for ? Not meath as a thruhull is it id think i need a scoop thruhull a hose to the pump and to the tank