New frag tank setup idea

[Texas Reefer]

I'm contemplating setting up a frag tank to temporarily house many of the corals in my main display. I have an ugly palyp taking over and going to try adding a matted filefish to eat them.
So my thought is a 20g long, stand, similar lights (t5's), and plumbed to my main display just adding a return next to the main return pump and the frag will drain to one of the main's socks. What do y'all think? And if any of you have one like this set up, could I see picks?

 

[Texas Reefer]

Drilled holes for overflow and return! Got the Sicce Syncra 1.5 357gph return pump, plumbing, Coralife Aqualight T5HO 30in light. Just need to paint the back black and get an overflow box.