Made some decent progress this weekend. Got the fuge light setup, most of the wiring done, started programming the Apex, and did a full leak test.
Found two issues:
1. Slight leak from both end caps of the UV sterilizer, should be an easy fix with new o-rings.
2. Only getting 400 GPH max out of the return pump (DCQ 10000, should do ~2,800gph unrestricted). I know I have a lot of restriction in the system, but need to get way more flow (shooting for 900 GPH). I think the main issue is the dual 1/2" Locline outlets that came with the tank. I'm going to up those to dual 3/4" and hope that helps, otherwise I might need to look for an even more powerful pump.