I am in the midst of applying a 3 part traditional stucco to a new home.  The 2 base coats were mixed and applied with 1:1:8 portland/lime/mason sand.  I used a 1:1:6 finish coat with white portland, and a Del Rey color additive.  The finish coat was applied, and has cured for 3 days.  Then my clients have attempted to disinfect their well with bleach.  They informed me that the bleach was rinsed out of the system, so I came by and gave the finish coat a spray down, since we were expecting windy and sunny conditions. 

The next day there was dramatic discoloration in a camouflage pattern across the entire section which I sprayed down.  I can see no indication as to why this happened where it did.  The blotches do not follow surface irregularities.  The temperature during this time period was between 45-70 degrees, with the humidity between 30 and 60%.  Has this ever happened to anyone here?  Does anybody know of any remedies to this situation?  My next guess to to re-apply the finish coat…