Does Salt Go Bad?

[racin24fan]

Back in the spring I bought a 48lb bucket of Instant Ocean Sea Salt. Since then it has become hard and clumpy. When I first bought the container the salt was similar to sugar. I had to take a screwdriver and hammer to chip it apart. It will disolve in a bucket and reads correctly, however, it leaves a scum like solid that I have to remove from the top of the bucket.
Is this still safe to put in my tank?
Any ideas? I do not see how it could have drawn moisture because it was sealed and placed in my closet.
Thanks for any help that I get.

 

[usirchchris]

IMO no. Might take longer for it to dissolve, but as long as it does dissolve you should be good to go

. There isn't anything organic in salt to perish as far as I know.

 

[racin24fan]

this film never disolves. its like cotton that stays at the bottom of the tank. I mean most of it does expect for this small layer of cottony like film. its almost like snowflakes.

 

[usirchchris]

Originally Posted by Racin24fan
http:///forum/post/2926108
this film never disolves. its like cotton that stays at the bottom of the tank. I mean most of it does expect for this small layer of cottony like film. its almost like snowflakes.
Hmm, that does not sound good. Never happened in any of my tanks anywho

 

[scaples]

My salt does that. whenever its exposed to air it can cause the salt to stick together. I just break it up, put it in the bucket and mix it. Just make sure it dissoves well. Never had any problems with it.

 

[bang guy]

Aquarium salt needs to stay dry & tightly sealed. Salt attracts moisture at an unbelievable rate and if it absorbs too much it will form clumps or even a solid piece.
These clumps are literally cement, it is Calcium carbonate that has precipitated out of the salt and is binding everything together. Although it is still safe to use the Alkalinity of the resulting water will be low and will probably need to be supplemented. Any "dust" or "clouds" forming at the bottom of the mixing container are just Calcium carbonate particles. They will not dissolve and should not be added to your aquarium water. They do not harm the saltwater as long as it is allowed to settle out before adding it to your aquarium.