This reply back is for cabezon.... you said you did not understand my question "The Overflow boxes inside the tank interfer with water ratio flow to the sump."
I was told that the Overflow Boxes that are inside the tanks (ReefReady) take up floor space, interfer with the water ratio flow rate and causes hot spots in the tank... Is this not true for Reef Ready Tanks?
OK. the function of the inner baffle is going to be the same as the inner box on a HOB. the water comes in through the teeth on the box or the black acrylic. however, in a reef ready, you can have holes anywhere along the height of the black acrylic, so that you intake water from the top (skimming), middle or bottom. You can adjust the flow better with a RR. As far as footprint, that is negligable, and aesthetically, I prefer the RR to the box that hangs. Plus you can get the tank against the wall with a RR.
If by hot spot, your friend means dead spot, that has nothing to do with the type of drain. if all you have is a drain and a return, then see above to the flexibility of a RR. But you won't, you will have powerheads. So dead spots are a non-issue.
if by "ratio flow rate" your friend means turnover, the number of gallons moved from the DT to the sump and back, that has more to do with the pump than the tank. Once equalized, only the amount of water returned will drain. remember, your drain, if you use flex is going to be around 2" ID. even given the turbulent flow, you will still move a lot of water. My pump is the limiting factor. I am not sure how much water my HOB moves, but I could attach another pump and see if it keeps up. i bet it would.
HOB overflows are loud, inconvenient, ugly and dangerous. I would avoid it if you can.