Siphon overflow design (pix)

[scottnj]

Rob,
Few thoughts.
First I think your idea of a tap at the top of the siphone or u-tube into the venturi side of a power head is a decent idea. I have been meaning to try it on one of mine that has a low flow rate to help with bubbles. As others have said though if you have enough flow rate through the tube it will not be an issue.
Another thing I did on mine which helps with bubbles as well is added a little baffle on the intake box around the u-tube. I was finding the flow into the siphon box was so much that it was causing water turbulance and creating bubbles that would go into the u-tube. With that added baffle its not a problem.
Lastly, on your question I would say don't glue it. I tried that the first time I made an over-flow and well it was bad lol. What I have done on the two I made sense then was drilled a hole and used nylon nuts and bolts and then covered / sealed them with aquarium silicon.
-Scott

 

[rob1116]

Thanks guys.
After dozens of phone calls and emails, I managed to find a IPS Weld-on distributer in Toronto. I ordered a pint of Weld-on #16. Any suggested tools for application/use?

 

[randy 12]

The first drawing looks very similar to the CPR overflow. Instead of using a venturi type powerhead like CPR has always done, they are now using a vacuum pump called an Aqua Lifter AW-20 by Oscar Enterprises (aka TOM). It looks just like an airpump but instead of blowing air out, it sucks water in one outlet (attach airline tubing) and spits it back out the other outlet (attach airline tubing). Basically, you hook the airline tubing that sucks the water to the top of your overflow tube where you have the nozzle, then you put the other airline tubing with the water coming back out of the pump, back into the aquarium. It's very quiet and works great no build up of bubbles, no break in siphon.