I hoping to benefit from someone else's experience. I went to the garage cabinet where I store my pond chemicals to mix up some liquid cutrine for some FA spot treatment. The unopened gallon jug 'rattled', as it seems 'something' had precipitated since I'd bought it last year. WAG would be the copper had come out of solution? Anyway, I took to vigorously shaking the jug, and while I was able to break up the clump of precipitate, it would not dissolve again.
Question: Should I dispose of this or use it anyway? I doubt it would cause harm if the copper had precipitated out, but don't want to waste the effort of spraying with 'bad' cutrine liquid.
I was just wanting some experienced opinions before I waste a $50 jug of cutrine.

Better to shun the bait than struggle in the snare.
- William Blake