prepackaged LS is a waste of money IMO. I agree with returning it to the LFS, if you baught it at one. I would return it and just buy some dry sand. The packaged LS could have high levels of nitrates and phosphates built up in it before you even open it or even worse it could have
hydrogen sulfide in it and it could devistate your tank, especially if the bag is that old. You are far better off starting your sand with fresh dry sand and either seeding it with an established tanks LS or just placing fully cooked rock on it and waiting it out. The problem with the seeding it with established LS is that you have a fairly good chance to get something you don't want in your tank unless the owner of the original tank is very reliable. The problem with placing fully cooked LR on top of it is that it will take a long time for it to get established and you will still have the likelyhood of recieving an unwanted guest in your tank. I did the fully cooked LR and now I am power feeding the sand to get the benthos to grow. I had some very mature LS in another tank but I am not a reliable source so I refused to use it.
