I just brought bio pellets, gfo, and carbon online, so I'm waiting to see effects before trying amino acids.
My purple rim monti is now a white rim monti and purples have faded on other corals too.
My understanding of the Zeo, is its a system of super low nutrients, carbon dose to get the bacteria (helps get to ULNS), then dose aminos. I think it limits zooxanthellae and their energy source, while upping the bacteria as coral food/energy source and the aminos needed for pigments. Thats my stab at it, please someone clarify/correct if you know more. Fish poo supposedly has all the aminos coral needs, but i can't argue with the looks of zeo tanks I've seen.
Following along, hoping for some input on what people have had success with in getting corals to color up better.