Mag-Drive 7 spitting air

[2poor2reef]

If the mag 7 pumps more water than the 3100 (and I don't know if it does) is it possible that it is pulling a vortex down from the surface of the sump's water level and sucking that into it's input? I had that happen to me when I upgraded to a more powerful return pump and did not increase the water level in my sump.

 

[esmithiii]

There could be a leak in the tubing after the output of the pump or in the pump itself that sucks air in due to the venturi effect. Also, any small bubbles that get sucked in become many smaller bubbles!

E

 

[rayt]

I have just installed a Mag-Drive 7 inline and it is shooting a fine stream of air bubbles into the tank. I first thought it was my bulkhead fitting's close proximety to my skimmer outlet so I experimented by removing the skimmer leaving the sump empty but that didn't help. I have a straight run from the sump through a union ball valve, into the pump and then up about 3.5 feet, through an inlet tube and into the tank. I have a small anti-siphon hole in the inlet tube but plugging it doesn't solve the problem. I used to have a Rio 3100 in the sump, before the protien skimmer, which used the same inlet tube with no problem (except for the pump going south on me!). Does anyone have any suggestions?