If your dosing something like Triton or trace elements..I'd stop that as well ..as dinos will feed of the trace elements ...is my experience...I recently got a microscope and confirmed that I have Amphidinium . So I would like to say thank you to everyone in this thread for treatment options and their experiences.
How does one know if they have small cell or large. Not that I am sure it matters all that much.
Have sponge excel on the way and will start an aggressive export schedule. I will also does NO3 as it and PO4 crashed on me (my fault, went super agressive on this tank at export and ended up too clean I think). Mine are super heavy on the sand sand (Except where my Goby turns it over) and a bit on the glass. Thankfully it hasn't messed with any corals yet.