Nice looking set up! Here are a couple things that might help you out in the future.
1: If you can, hang your lighting rather than fixing it to the canopy, that'll let you adjust the distance to water's surface should you ever want or need more intensity.
2: 125's aren't tall enough for Altums. A full sized adult can have a finspan of over a foot and 18 inches (minus substrate) isn't really enough room for them to spread their wings. Wild type Scalare may be a better choice for the long haul. With all that sand, discus would be happy in there too.
3: If you're going to have a lot of epiphytes on that wood a water mover pushing a current behind it will help keep fresh water circulating around the roots. I've found Anubias in particular appreciate that a lot and it'll help keep detritus from settling down in places you can't get to.
Hope this helps!
Cories! Get a lot of Cories!
I bet they'll love it in there and spawn like crazy.
Looking forward to seeing how this tank matures. You've got an eye for detail that will serve you well.