External Sump pump, too powerful?

  • We are currently upgrading MFK. thanks! -neo

Madayew

Feeder Fish
MFK Member
Nov 5, 2009
56
0
0
NC, USA
So today I started to set up the tank. I took my sump outside and connected the water pump to it. There is a 1" PVC inlet pipe from the sump to the pump, and the outlet on the pump is also a 1" Pipe reduced to the half inch rubber hose. The sump had a downward slope with gravity feeding water to the pump. My pump only works when the gate valve is halfway turned. If I open the valve all the way it loses the vacum or suction. The pump is a gen x 3, rated around 900 gph. ideas? I was simply holding the outlet hose while it sputtered water out of the sump. Once it is opened more than halfway it loses suction.
 
How much water was in the sump? I'm a bit confused. The pump should never have suction, the water should be available to the pump at all times.
 
the sump was filled with 15 gallons or so
 
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