Overflow box help/questions

[Milad]

I wanted to get an overflow box going on my tank.
Currently at one end, 10inches down and 5 inches from the walls there are two 1.5in holes drilled with bulkheads

If i built an overlfow box, I would have to put it 8inches deep into the tank and I dont want to take up that much room inside the tank.

What I was thinking is building a overflow box outside the tank and letting the 1.5in holes just carry the water to the overflow box and then having 3 1in returns back to the sump.

What do you guys think? is there an obvious flaw im missing?
Here is a model of the idea.

[Bloodasp]

Looks like a better idea than the one you originally had. Not that the one was bad I just think this one would be a better way to go.
Probably use glass panels siliconed into your tank.
one thing im seeing though is that the water level will drop pretty much to the length of the lowest pipe. And if you are trying to build that original setup you were interested in that would mean a lot of water going into your sump.
What would be good would be to add a glass in between the overflow and the return pipe which would be as high as where you want your water level to be.

[Milad]

you ever seen this done before?
should i be putting a strainer on the holes?

I think overall it will look much better. I just never silconed anything. Hopefully it doesnt just fall off. lol.

[Bloodasp]

Not quite the same but external overflows are pretty common but mostly the holes are on top. but i think working with what you have now that it wouldn't be an issue.
Speaking of strainer holes I was jut about to say. You wouldn't want your fishes getting into your overflow.

[Milad]

Here is the updated design
Its made out of .5in glass. i had to make a lip at the top because of the rim on the aquarium

The return also goes through the overflow box
Im going to put new bulk heads in that hold the overflow box to the aquarium for extra strength. Im also going to paint the back of the aquarium