saturation
 

if my salt mix is left open to the air is it possible that it can become oversaturated with moisture and thus not dissolve when i go to make my salt water for water changes?

Highly doubtful. You'd need a heck of a lot of water to form a saturated solution from a bucket of salt mix. Still though, I wouldn't suggest leaving salt mix out in the open... you never know what sort of stuff could float in there.

-Rich

If it's really a concern with you then just add water as it is and make it into a soupy mixture, measure it into your mixing container and set your salinity. There is a two part salt mix and that's how some people deal with the little bottle, just add enough water to the salt mix to make it soup and then add the little bottle and mix well. Sounds messy to me but it works for some people.

Doug