Modification of overflow box

[oceanjumper]

I have a sump and I want to add a refuge to my setup. I want to let gravity do it all, so that water from the main tank falls partly into the refuge (~20%), partly into the sump (80%). The water from the refuge will eventually also drain into the sump, and a CAP 2200 return pump is sitting in the sump for the return to the main tank.
Some use a small rio as an additional sump pump to the refuge, some use a tee on the drain of the hang-on overflow box. Well, I have not much space behind my tank to install a tee. As such, I thought of the following:
Add another bulkhead to the outer-overflow box, at a level between the top of the drain and the bottom of the U-tube. I think that should work. See also attached pic for more details.
Has anyone done this before? Does it indeed work? Are there drawbacks?

 

[slick]

Looks like it would work to me. You might have to put a ball valve on there to slow the water down.

 

[richard rendos]

Looks like it will work like a charm. Ball valve is a good idea.

 

[cap'n pete]

Looks good. Just make sure the U-tube goes past the new bulkhead like the drawing.

 

[broomer5]

It'll work.
As others mentioned - you'll need a ball valve for sure.
When it comes time to prime your U tube - you may want to block off the additional fuge drain, and fill the outer box up until it's completely full again.
When you suck the air out of the U tube, you want to make sure you have enough water in the outer box so you can prime the tube.
All depends on where you drill the hole, and how large your outer box is I guess.
Neat idea.

 

[oceanjumper]

Thanks guys~
I will assembly it as soon as I have the supplies in.
Instead of a ball valve, I was thinking of using a flexible hose and one of those clams that they use in hopitals on IV's. The ones that squeeze. Remember them? I like the idea of really seeing what goes on in the hoses, especially the valve (if stuff builds up there or not).
Priming the tube might indeed be a little more complicated if not enough water is in the outerbox to fill the U-tube when air is completely sucked out. I might need to add water simultaneously as the air in the tube is removed. We'll see. In any case, I am going to drill the second bulkhead (0.5 ') just under the top of the drain (the bulkhead to the sump is 1').
I will make some pic's once everything is setup.
Cheers, Marc

 

[hudsonth]

He has some modifications to fit external overflows, I am in the proccess of making the whole overflow for my future 170 gal tall.

 

[hudsonth]

www.rl180reef.com/frames.htm