Been busy between yesterday and today! Rockwork placed inside the tank (which is always the most nerve-wracking part to me...)
Got the plumbing finished:
Started filling the sump...
And adding sand + filling the tank!
Had three small leaks with my plumbing: two were halves of elbows that I'd missed gluing after dry-fitting, and the third was the right return bulkhead that I had to clamp down REALLY tight. Got them re-cemented, tested, and my manifold + return have had no leaks so far.
Aiming to finish filling it up tomorrow, mixing in salt to 1.015, testing ammonia, and adding 500 gallons' worth of bottled bacteria to kickstart the cycle.