Calfo Overflow Design Question

I'm doing a bit of research on system design and the state of the art at the moment seems to be the Bean Animal drain system coupled with the Calfo coast to coast overflow box; I can see why.

Has anyone ever considered beveling the inside edge of the vertical overflow wall (i.e. the tank facing edge would be a 90 and the inside edge would be 1/4 round - radius would be ~.5 glass thickness)? Having never actually seen one in operation, I'm not sure if this would provide any benefit at all. In theory, due to surface tension the water would adhere to the glass wall and there wouldn't be any splash at all.

Thoughts anyone?

--EW

 

I have an acrylic frag tank with a 20in c2c overflow and external overflow box, and the manufacturer did bevel the edges using a router like you mention. its on 5/8" acrylic, so there is a pretty decent roundover, at least 1/4 round.

I understand your concept, and I think it might have a valid point. Initially the water cascaded over the lip like a waterfall, however over time it gradually "stuck" to wall like an infinity pool. I believe this has to do with the surface tension in the water, as well as the development of a slippery biofilm on the back glass that takes a few weeks to form, kind of the like the build up in plumbing that seem to quiet down after a few weeks.

I also believe water flow is another important factor, coupled with the overall length of the overflow lip. The longer the lip, the more flow it could spread out, whereas as on a shorter O.F. Length high flow could build up a waterfall.

 

Thanks Sno, the "slime coat" concept makes sense. In the meantime, I created this just in case I wasn't making any sense....

 

I built mine out of glass, coast to coast on a 36" tank, and mine is not beveled at all and the water still clings to the glass and doesnt cascade and splash. In my opinion it would depend on the length of the overflow box and the flow of your return pump. The shorter the box the more water has to flow over the edge with the same flow. I could see with a short box and a high flow return pump where you could get alot of water flowing over the edge and maybe this design would help a bit.