Feedback sought on new frag tank

[Moto69Joe]

I am about to have a 30" x 24" x 12" AIO frag tank built. I will have a skimmer in it, LED's, and mangroves in the back compartment. I have two designs I am thinking would work for the rear compartment/filtration but I am new to this and not even sure if it will function as intended. Any criticism and advice is welcome. I am a fan of the last design as it closely mimics my Biocube setup.

 

[BeckMBSC]

I'm thinking about getting into frags too. I'd like to know how this works out for you. I love the design, and would like to use this. Thanks!

-BeckMBSC

 

[Fishman793]

I personally like to have my skimmer after any chemical media, not sure why, but I just do. But that aside, the second design looks very nice, and one I would use.

 

[Moto69Joe]

Can anyone give me some help with designing in an overflow into the rear compartment? As you can see on my 2nd design I won't have the 2nd wall go all the way to the top to allow water to flow into the 4" channel should me polyfilter back up. Is there certain height from the top I should have this wall end? How tall should I make the two walls that will support the mangrove compartment?