I'd for sure run GFO as I've seen negative effects with acros at 0.18 ppm. I'm sure you can acclimate them to higher phosphate levels but then you'll lose out on good growth as it starts to inhibit calcification.
Biopellets on the other hand, at 10 ppm nitrates, I don't feel like you really need to kick them up. I prefer to keep nitrates around 5-10 ppm and if you are getting that naturally, I say leave the carbon dosing out of the equation.
What are you getting for a CaRX? Those are always fun purchases!
I'd for sure take that credit for the BML. For as little function as it serves on your system, cash that baby out and get some other much needed item on your system.
Where's my pic of you feeding fish? [emoji13]