Any and all help is appreciated!
So the boss found out I have some aquariums at home (a meager 17 gallon and 6 gallon) and he thought it would be fun for me to do a huge 320 gallon

tank we have installed.
And I am asking for everyone's guidance on this since this is definitely not my home tanks.
Acrylic tank: 72" x 36" x 30" with built in overflow
Lighting: LED?
Filtration: Sump or Fluval FX5 or Eheim Pro 3?
Hardscape: ADA horn wood, rocks and gravel (unknown type)
Substrate: Decorative white sand
Flora: Unknown
Fuana: 7x Angelfish or Discus (center piece), 100x smaller schooling fish for background (2 or 3 different species)
Budget: $2,500 for everything (except the tank)
We will have walnut millwork around it to hide the edges. What the big guy looks like:
The area I have for equipment:
OVERFLOW!
Inside of the overflow...
So my first task is, how do I filter this thing?
This tank already has 2 holes drilled in the middle of the tank and 4 in the overflow. SUMP? I honestly do not know why there are 2 holes in the middle of the tank and 4 in the overflow. Can someone tell me what each of those holes were meant for? I can understand 2 holes in the tank, but not 6.
But if I went for a canister, I could just plumb the holes for the canister and plug the unused ones.