Brett, I stopped using GFO back in the spring of - I think - 2016, and haven't looked back.
No GFO, no carbon. I dosed some liquid NO3 and PO4 for a month or so to balance stuff, then stopped using reactors for both.
Using GFO is like adding iron to your system - algae fuel.
I currently, and for the last 3 years, use nothing to combat nutrients.
I keep liquid NO3 and PO4 on hand just in case, but have used neither since Spring 2016.
My tank is a bit low on nutrients as I don't have enough fish, but my corals are doing OK.
Current params are;
Alk 8.3
Ca 420
Mag 1350
K 400
NO3 0 could be higher
PO4 0.013 could be higher
I really need more fish to feed my corals
