Loud Sucking Sound

[Dez]

I would just get rid of that first standpipe (tornado one) and make the emergency one taller (almost to the height of the overflow itself). This is how I have mine set up.

[Snufflupagus]

Alright, cool. Thanks for the advise guys, I'll work on things and see what I can pull off.

[The Grizz]

Try to turn the valve on the shorter standpipe closed a little to raise the water level in the overflow so that the water level is about an inch from the top of the taller standpipe.

[monocus]

make a stockman standpipe

[Snufflupagus]

Thanks guys, raising the water level dud the trick. Cheers.