Absolutely stunning! I am curious about your filtration system, it seems to be working really well!
I noticed that you run a de-nitrification reactor, I don't know many people in the US that run these reactors, can you tell us more about this and how it is beneficial to you system?
Also the stack of media in your sump, does this get clogged with detritus? How does the water flow through the media, looks like you have a filter pad prior to the bio-balls and it drips down.
Do you run a refugium with algae?