I mixed and used half of a container of ALK and let the other half sit as I normally do. Went to fill up my doser, and the solution solidified again, like when you first purchase it. I went through the process of mixing it again, but it doesn't seem to want to mix. The solution just settles on the bottom. Does this stuff go bad? I assume it isn't safe to use if it keeps solidifying......now I don't even know if the first half that I did use was mixed correctly. The remaining half of the bottle might be twice as strong. I have been using this stuff for almost 2 years with no issues.

