salt still OK to use?

[chuckm]

LONG story-short......I came across some salt that is 10yrs old (misplaced in basement). Can i still mix it up and use it in a reef tank w/ sps,lps, inverts? It is Intsant ocean brand. It's clumpped together in spots, color is the same though.....Just wonderin' or should i save it for the driveway?

[jimsflies]

The short answer is: use it in the driveway. It may be difficult to get it to dissolve fully when mixed.

With an air tight seal, the salt mix should be good indefinitely. Unfortunately, a container can seem to be closed/sealed and still not be air tight. As a result, over time your salt will pick up moisture from the air. Big deal you might think, but many salts that are highly soluble in their anhydrous (or water free) forms become much less soluble in their hydrated (or water associated) forms.

So, in all likelihood your old salt mix has probably been highly hydrated and thus you may have some issues trying to get it to dissolve. Compounding the moisture problem, your salt could also possibly adsorb carbon dioxide from the air. It is then possible that some of your salts have formed carbonates which can cause further solubility problems.

If you were really intent on using it, you could first try to dissolve the salt as you normally would, but give it some extra time to dissolve. Hydrated salts may seem insoluble at first but may just dissolve very slowly. If you can't get all of the salts to dissolve despite heating and giving it time I don't use it. Also before you use it check its pH (if it has formed carbonates and dissolved the pH would be out of whack). If everything looks okay go ahead and use it.

[larryandlaura]

Very well put Jim.

[chuckm]

thanks for the input, that's what i figured, i just did'nt know the shelf life of salt mix.
It was a 200gal. box w/ 4 bags. so it was by no means air-tight.
It's just that I'm a cheap bugger, and hate to throw things away.
I may mix up a small batch to test out of curiosoty, or keep around for absolute emergencies.
thanks again!