Slurry question

[Bronzie]

I was wondering if anyone knows if slurry hardens can it be reused? Is it
still good quality? Someone told me that it can last a year. However when I have mine stirring in tank it would evaporate before a year. So do I let
it harden and then add more liquid. Anyone have any information it would be appreciated. I have a 36" stock tank that has a motor turning a paddle wheel in that I use to stir it. Has a wooden lid over it. But if I don't keep adding
liquid it gets real thick. By the way I use remet. Anyone have any information it would be appreciated.