I thought that maybe you needed to crush the Vitamin C tablet thinking it may have a "coating" on it's shell...However, I just checked my pool with the tablet alone and the stain came right off..... Sorry Michael !! thought that may have been your issue.... Things are looking a bit better for you, so I have been reading ?? Mine is now on auto-pilot, and the dramatic changes I saw over the weekend have now subsided....it's better for sure, but definitely not what I'm accustomed to seeing...