Does anyone run their overflow box without an emergency drain?

[ReeferinTX]

Does anyone run their overflow box without an emergency drain?
I'm have a heck of a time keeping my overflow tuned. I think it's because the box is too small. I have a gate valve on the main drain so I can make very small adjustments, but any change (like turning down the flow pumps to feed) causes overflow into the emergency stand pipe.
I'm considering just putting a strainer on it and making the emergency a second drain. Any experience with this and advice would help???

 

[gastone]

I've got two classroom tanks that feed into the same sump. Both have a dual drain overflow box. I was going to go with a modified herbie, but in the end just ended up going with a single taller standpipe in one of the downpipes and nothing in the other. The downpipe with no standpipe is the primary drain and has a ball valve (didn't feel like springing for gate valves on my school system) and the standpipe with the downpipe would act as the emergency, but I've found that I achieve a quieter tank when the emergency pipe is getting some flow. I don't have to fiddle with it. Runs smoothly and quietly. Not whisper quiet, but it's white noise as far as I'm concerned.

The water level is barely over the drain on the right in this image. More than a trickle, less than a flood.

 

[Sassafras]

Getting the flow just right is a fiddly adjustment and the size of the box might be your problem factor. I always run the three-drain beananimal configuration, but I run it with 100% of flow in the main drain and nothing, or a tiny trickle, down the secondary drain. Run that way, it almost feels like I have a dual emergency overflow setup since my emergency drain never sees any water. Unless you are getting a serious amount of flow down your emergency pipe during feeding and such, I wouldn't be too uncomfortable running like you are.