Hi this is my first post thank you for your help. I am making toner with rosewater and rose hydrosol. I read that .15% potassium sorbate with .05% citric acid would preserve these toners so that is what I am using now. When the ph is lowered to 3 to make the solution safe does the lower ph change the good hydrating properties of rosewater and the hydrosol? I ordered Optiphen plus because I wanted to preserve the original ph of rosewater but now that I found this site it seems that it may not mix well in water? Second question, when I use orange peel powder to make a serum and only use glycerin and oils with no water added, do I have to preserve? If I add witch hazel to the serum will I have to preserve? Thank you!