* Do you really want to use socks? Maintaining them is a chore I don't look forward of doing in my next system design. I like the approach of Jeff at lifereef system. His sumps are sockless, he just use sponges to tramp large debris and micro particles will be exported via skimmer and refugium.
* I also don't like the idea of placing the refugium in a high flow area. I believe refugiums are more efficient exporting nutrients if there's enough contact time. I like being able to slow down the flow in the refugium. If you like this idea maybe you should place the refugium on the right side before the frag tank. Feed the refugium from a T off the return pump, using a ball valve or gate valve to control flow. Flow will be slow going thru your frag tank but that can be easily solve by adding a powerhead.
Who manufactured this sump?
Tsunami? Really? Huh, I have not seen a sump that looks like that from them. Learn something new everyday. I kind of discounted them but might have to reconsider. That's more like my trigger systems sump which I love.