Kalk Powder "shelf life"

[Djplus1]

Just curious, as literally every online search seems to devolve into "mixed" water lasting for so long with a lid on, yada yada, but does kalk powder (Calcium Hydroxide)  technically go bad? I have 2 "opened" containers, one ESV and one Seachem and each are still very powdery (ie not clumpy or solidified) so are they still good to chuck into my kalk stirrer without any real issue?

[ReeferMan]

I use stuff from 15 years ago and works fine

[Djplus1]

OK perfect, that's what I wanted to hear as mine is probably close to 15 years old too. Do you compensate in any way, as in use twice the amount or whatever? Or is it literally exactly the same as if you just opened a new jar?

[ReeferMan]

I treat it like a new jar. If its still dry I would still use it no problem. 

[DaJMasta]

Yeah I think the issue is when it's mixed up and comes into contact with air, then it slowly looses potency.  Before that, as powder, I think you're good unless maybe it's stored open in a humid space or something.