Compliments on a fabulous clean up job!, Set up looks awesome!
One thing I noticed that might be of interest, in the pictures, theres one that shows a glimpse of the inside of the canopy.
If you built the canopy, did you water proof the inside?
I ask because I made the mistake of not doing it to mine and the wood delaminated over time (oak ply) I learned my lesson and after rebuilding the canopy, I sprayed the entire inside with white epoxy paint.
As for purchases and whats next, I would suggest looking into an RO/DI unit and an auto top off plan. The ATO is a great item to have and will help you keep your tank full without you always having to add water. There are a number of ways you can do it and the cost can be pretty cheep to as elaberate as you want to go. (pepsi bottle and tubing vs LitermeterIII) Look up melevsreef and check out the ATO he does. Its DIY simple as it gets. Also, not to sound like an advertisement for him, but he sells a RO/DI unit at a great price.
one other suggestion on cost, when u buy your rock, dont waste money buying all live. Use dry base for the bulk of your rock work and add a few pieces of live rock to seed. Since it sounds like you are taking your time to get things up and running while you save as you go, the base rock will have plenty of time to "mature" before the system is completed. it only takes a couple of months for the coraline to start growing everywhere.