Water from overflow under or above water in sump?

I'm putting together a sump with some of the overflow water going to the fuge, and the rest to the skimmer section. When I do the plumbing, should the pipe be under the water level in the fuge or sump? I've heard of some people using a 90 degree elbow right at the surface to agitate it and provide some oxygen. That would cause noise and bubbles though?

If the water enter the sections under the water level, it would certainly be quieter, but what is the trade-off? More bubbles and less oxygen exchange?

 

Not if the flow is slow going in the fuge. i have mine breaking the surface and no bubbles.

 

I'd have it under to keep down the noise.

 

I run the fuge at surface level and the sump under the water.

 

agreed that as you only want very low amounts of water going through the fuge
that having the flow close to on on the surface should not manifest as to noisy

you are looking for 5x fuge volume or less going through there per hour, so its no louder than a typical internal cannister filter IME

Steve

 

Thanks--the fuge flow makes sense. My fuge is quite small--6x10 inches by 8 inches high so water volume will probably be about 3 gallons so I'm thinking 30 gph for the fuge. If it can be that low then I will certainly break the water surface. The sump I will run under the water level in the skimmer section. If my baffles don't solve the bubble problem I suppose I can always put some foam in there. Thanks.