Finally got it filled... I went with a low lying aquascape so I can fill in the tank with macroalgae, gorgonians, some softies, and maybe a few LPS. There is some very unhappy xenia on the right if you look carefully.
I fragged a milli from my last tank before I sold the colony so I could use the dead skeleton for something the seahorses can wrap their tail around.
DSB is about 3" deep. The bottom layer is mixed Caribsea mineral mud and sugar sand (2.5"). The top layer is sugar sand (0.5"). The mineral mud felt more like peat moss used for gardening.
Still a lot to do. The electrical is a mess and the overflow needs to be adjusted. The gate valve on the siphon makes a loud sucking noise.
I won't be adding sea horses for some time... still need to let things stabilize and add macro/gorgonians to give them plenty of tail wrapping options.
Also, I chickened out of going skimmerless and bought a Vertex IN-80 from J&L. Maybe a bit undersized, but it was a good deal and I'll have a lot of algae in the tank. It has already pulled out a lot of sand. Unfortunately I lost the plug for the skimmer cup drain, anyone know where I could get another one!?