How to combine two tanks for a sump?

So in the process of a new tank build, and need a sump for it. I have a 5.5 rimless and a 2.5 aga on hand that will be combined somehow to create the sump.

Since the 5.5 is rimless, I thought about using that as the display fuge and having it overflow down to the 2.5 with a 1 inch herbie style overflow. Going to keep it as quiet as possible and this was a good route.

The tank will need to be elevated a bit so water can go down to the 2.5. I am hoping it should be enough to hold back flow from the return.

Not sure if I want to keep it simple with just a hole for the 5.5 herbie or put in baffles and all that yet.

 

would have 2 overflows into a common sump and then two returns. build a manifold with a ball valve on each return line and you will be golden. I can make you a terrible mspaint picture but i bet you get it.

 

Very interesting idea! Those are some tiny tanks. Good luck.

 

Its just one display with a herbie overflow down to the fuge tank, and then an overflow down to the return tank, and a single return back up to the display.

Basically just going to be a sump that is separated into two tanks instead of one tank being separated into sections