Depending on your fish load, how often you feed, and your skimmer's ability to process the nutrients, you maybe do not need Zeo Mix at this time. While the stack method is great, it really works best when the user has a high bioload. I would always have carbon in a carbon/bac driven system, as far as I know, sort of a staple. Double check the skimmer, make sure it is pulling dry skimm as well. Sounds like your nutrients are lowering, so the corals are making adjustments, the pigments should return, but you will see tones a bit lighter, those deep dark saturated colors will pull back, but what you seem to be experiencing is paling of corals due to lack of food, so I would feed the fish more, and continue dosing to maintain low values. Cheers