Hello, sometimes when I test for phenolphthalein after making my liquid soap, there is a slight pink color. Since there is little solution left, I add a very small amount of citric acid to neutralize it. It works very nicely. But citric acid sometimes doesn't dissolve completely. Or it may not mix completely as a white cloudy layer. I have shown examples in the photo. What advice can you give about mixing citric acid completely homogeneously?