Lighting:
LED's seem great, but I've always loved T5 and MH technologies.  This tank is now a mixed reef so I have to be kind to my LPS as well as giving light to the SPS that grew from the previous encrusted parts that stuck around.  Over my 75G tank I have 4x54W T5 HO bulbs.  I'm now using the Tek T5 retro with the reflectors, below is the par readings with a single flat white reflector, and I will update soon with the parabolic reflectors as well.

Filtration:
I use a 29G sump, but to keep things quiet I have a return of only 60GPH.  This will turn over the real water volume about once per hour.  I use a filter sock, I do this to try and raise NO3 which had always been 0, I also dose NO3 weekly to achieve a level above 0.  I find having NO3 has naturally suppressed P04 numbers.  The sump is basic, I use a Bubble Magnus Curve 5 running dry enough that it needs the cup emptied about once per week, and I have 1/4 cup Po4 remover in a mesh bag inside the sock which is replaced monthly.  I have an Ehiem pump for return and I monitor flow with the Apex.  This is great because I can kill things like the heater if flow drops below 5gph for some reason, that way I don't cook the sump because my return failed.

I like to target NO3 levels of 1, and PO4 below 0.1, i'm fining my PO4 value is usually 0.04 which is a touch low for this tank, but I enjoy only cleaning the glass every 4 days so I'm hesitant to change my methods.