PhosGuard shelf life

[mfinn]

I have a opened bucket of PhosGuard that has been sitting for a couple years.
I would like to use it now. Is it any good after a couple years?

 

[mfinn]

I would think it would be ok. I has stayed dry, but not sealed.
Anyone have a educated opinion. Good guess?

 

[SeahorseKeeper]

I would shoot the manufacturer an email. I'm on the fence about whether it would still be usable.