I use the Sta flo concentrate in the recipe I posted above. I have had no instances of it flaking, caking, or showing on darker colors when used in this manner. I haven't had to look for it lately as the bottle I have has to be 4 years old. It goes a long way. I do believe I originally purchased it at my local WalMart but know I have seen it at other grocery and even places like the Ace Hardware. I make sure I shake the bottle well before spraying. Ann in TN