Spitting? If the dosage is raised too fast, some folks have noticed some precipitation/cloudiness to their water. I have never had this issue. Many other things have been blamed on their dosing of VC but It may have only been coincidence, as thos things may have happened in their tanks anyway. I keep a very mixed reef of sorties, zoas/palys, clams, anemones, LPS & SPS & have never experienced any negative issues. I have been dosing ~23ppm, 2x/day, for well over a year now.