if you want, just shop around, check the sponsors on this site, go to all the cool fish store websites you can think of, and pick one that you think is best. i would suggest going with the u-tube design.
If you get chronic bubbles in your overflow U tubes, you need to speed up the return pump so that you are running more velocity thru the tube which will sweep bubbles on thru.
Also the height of the inside box in relation to the U tube intake counts, if its a long drop thru the slots and and the U tube oickup point is close it can suck bubbles directly into the tube, often a short length of vinyl tubing to move the intake closer to the bottom will help
Overflows are a reliable way to get things done, IF you understand how and why they work. Drilling is better but requires the tank being down, getting some one to drill it and guarentee the job, as well as building a decent overflow wier after the fact or coming up with creative solutions to getting surface skimming action
So Doug, I have the u tube positioned so that it doesn't suck up the bubbles that fall from the slots. About the return pump, your saying to open it up all the way with no restriction so that it pumps more water back into the tank? Wont that increase the tank water level and possibly drain the sump?
Heres the fix for the utube blues (in part) The velocity Doug is talking about can be sped up by having the drop into the second box farther down. The level in the second box needs to be well below the tank level. This will create enough gravity on the down side so the bubbles just go along for the ride. If you go with a hang on overflow, get one that has a divider in the second box (the one on the out siode of the tank) The utube will drain into one chamber and the water will overflow into the second chamber in the box. The second chember has the bulkhead for the drain to the sump. This is what I had on my first tank. One of the big advantages to this design is that if the power fails, the first chamber holds water so the utube wont empty and lose siphon. That way when the power comes back on, it will start on its own via gravity. That prevents a flood and drained sump and burned out pump. Heres a pic of mu old one. You can see the divider in the outer box, I had to lower it with a Dremmel so the water had enough distance to fall in order for the velocity to prevent bubble build up and also keep up with the return pump. The overflow is made by True View.
Thanks Robert. I Dont have to have a divider because the way its designed is that the u tube is very long and gets one end submersed into water in the second box. Once the water level drops below the raised stand pipe, the u tube end is still submersed so it doesnt loose it siphoon.
John, those pics are after the tank was torn down. I had a stockman in the overflow so there was a constant lvel in there too. Its best to take every precaustion because the standpipe wasnt glued. This could over time drain completely. That is why the divider was the safest bet.