1 year old pucks still OK to use?

[drband]

should be good for at least 2 years if sealed and unopened... maybe longer.

I've done the same thing!

[CarlD]

If no water got to them, they should be fine.

Be sure to check your CYA before you go...It WILL rise and pH will drop. If you are leaving floaters of pucks for 3 weeks, I would raise pH to nearly 8 prior to leaving--it will probably be low when you come back.

I did that once: Left 4 floaters full of pucks, set wide open. Came back to a clear pool but CYA had gone from 30 to 60, and pH was below 6.8--I rushed to get 2 boxes of Borax in--I think it took 4 boxes to get the pH back to the mid 7's.

I'd probably go with less floaters than that....