No overflow box stand pipe only

[soontobeareefer]

I'm re-sealing a 120g I got and I'm thinking about running a stand pipe only drain and return system. I know there are certain benefits that come with an overflow box, but as for pure mechanics it will still drain. I would have a 1" drain and an emergency 3/4" drain fed by a single 3/4" return line split into 2 -3/4" lockline and 1-1/2" lockline.......thoughts please....

 

[DCR]

The amount of flow you can get down an open top 1" gravity overflow without much noise is going to be pretty low for a 120-gallon tank. You could make it an internal Durso to help take away the noise. If you are thinking of making the 1" a full siphon submerged under the water level and have a trickle always going over the emergency, you could get a lot more flow, but I would think it might be difficult to locate the full siphon close enough to the water line to avoid overflowing the sump and still not get a vortex on the full siphon. I would try to use an overflow box if at all possible - even one of the siphon types that avoid drilling the side of the tank over a standpipe.