I have a large uv (largest I could get) 120 watt. I have manufacturer recommended flow through at 1100 gph for treating parasites. I dose trace elements (Right now using Prodibio Coral colors trace elements). I'm also dosing manganese and chaetogrow as I have an algae turf scrubber and it lets me know when I ran out of something as the algae all bleaches out white on the screen. That said, between using chaetogrow and trace element dosing I have no issues growing macro algae in the turf scrubber, using the UV, and dosing trace elements for corals. I keep tons of SPS - acropora, monticap, cyphastrea, tons of hammers and frog spawn, all growing crazily, and I have some orange yuma and I have BTAs, that also reproduce and grow big relatively rapidly (seem happy not angry). I feed heavily as well, 10+ cubes of food per day + a sheet of nori.
Obviously anecdotal, but I don't see signs of missing trace elements. Maybe the food contains trace elements as well that gets trapped in the water column?