While squirting in No Mor Problems, blue droplets are spilled on the concrete pool deck and allowed to dry, forming blue stains.
The blue dye in the product penetrates the concrete to form a stain. Typically this is not an issue if hosed off in the same time frame as the application of the No Mor Problems. However, if left to sit, it can permeate into decking and leave a stain that is more difficult to hose off.
First and foremost, hose off the deck after treatment to prevent any staining. However, if allowed to dry and the stain can't be hosed off, here are additional options to remove the stain:
Pouring scalding/boiling water on the stain (might take a few applications)