Having only one drain line from the main tank is ASKING for trouble.
Obviously it's a basement sump so noise isn't a problem. Are you planning on using filter socks for the drain? Something to counter splash would be good.
What's feeeding the AquaC? Can't reall tell there.
And the side and bottom drains on the refugium? Is one a backup?
Some suggestions... Having only one drain line from the main tank is ASKING for trouble. Not IF, but WHEN a snail gets in there and clogs one up, you'll have a wet floor and a dry pump. Also, it's a good idea to strain relieve your pipes so you don't put too much stress on the glass in your display tank. Maybe you've done some elsewhere, but I don't see it in the pic. And finally, the electrical direclty under the drain scares me a bit. Especially with the union right there.
Is that a pre-fab drain setup in the display or did you do that yourself? FWIW I'm never comfortable with cutting the bottom glass since I'm always terrified of what happens when the Oring seal at the bottom leaks. Whole tank drains then, where if you have a side drain, just a few inches are lost. But, since you've got it, does the overflow box there have holes in the bottom, or just teeth at the top? And is the top open? If you close off the top so snails can't get in there, you've at least mitigated some of the problem. I would suggest developing some sort of removable screen mesh, or black egg crate, or something like that. Anything that will allow you to clean the teeth on the overflow box but keeps bigger things out.
Fwiw I love my Aqua c .. Even with a outdoor cover on the outlets, You might want to put a piece of epdm attached to the wall higher than your union and extending down to your sump. Kind of like a flap just for added security .
Please forgive my ignorance, but could you comment on what you mean by "strain relieving" pipes and how it helps?
Basement sump.....go with a much bigger sump....you will be glad in the long run...rubbermaid tub.
Why do you feel you need baffles?
they are not needed
Just some thoughts....