I bought SN last December, is it still effective now?

[willowtree]

See title question
Maybe a dumb ass question, I wouldn't know
But how long does SN stay "effective" or potent?
I always kept it in room temperature closed

 

[IrRegularjoe]

Same, I have no reason to open mine unless. I think people will probably tell you to aquarium test it or blood test it. I could be wrong though.

 

[AnxietyAttack44]

It can last for years if unopened,or kept sealed. It should be fine. You can always test it before using.

 

[mediocre]

I got mine in September it has no expiry date so I assume it's ok.