I think Vibrant is carbon dosing .if you are not reading any PO4 or NO3 you should not be carbon dosing. You are worried about using Fluconizole, but not worried about dosing Vibrant? I’ve had 2 friends crash their tank with Vibrant. We used Fluconizole in our shop tanks and personal tanks will no I’ll effects and found it very affective. You will need to turn your skimmer off during the treatment so you will need to air rate the water to keep the PH stable