Venturi on powerhead?

I'll be using a Rio 2100 (692 gph) with a spray bar in my future 75g aquarium setup. The Rio does not have a venturi on it, but I like the look of tiny bubbles in the current. I suppose the extra oxygen in the water wouldn't hurt either. So I guess what I am wondering is:

1- Would adding a venturi to the powerhead be beneficial to the fish (darters, shiners, etc)?

and

2- How would I go about adding a venturi to a Rio 2100? Maybe just drill a hole in the spray bar near where it meets the pump, and attach airline tubing to it, running the other end of the tubing to the surface of the water?

Thanks in advance, I appreciate all the help I have received on the forum.
-Jake

2) It would be best to see how the spray bar is set up, but a simple piece of aquarium hose running from above water level into the faster flowing water jet will create a venturi. You merely have to point the end of the hose in the same direction as the water flow, so that water is not jetted directly into the end of the hose. Where you do this really makes no difference but the faster the water flow at the end of the hose the more air it will suck through.

1) It certainly cannot hurt. If you have a planted tank and wanted to maximize CO2 certain details could be argued for certain strategies. But for the fish plenty of dissolved air exchange will at worst make pretty bubbles and provide needed oxygen if the fish and bacterial oxygen consumption taxes the existing air exchange.

Edited by mywan, 27 February 2011 - 03:25 AM.

For me noise is an issue, and for that reason I don't like venturis. My main tank is in my guitar room.

I run a venturi on both my powerheads. Instead of using a hose up to the surface, I have a small airpump with one line split into two going to both the powerheads. This allows me to run it on a timer. I have the air setup to come on and off during the day. This helps a lot during the summer when it tends to be warmer inside. Also, most darters, most, live in riffles and that is a high dissolved O2 area. I run the air pump almost all day while I'm at work, and longer during the summer.