Can I use Sea
salt to make this solution?
Just use pickling
salt. It's pure salt with no additives or anti-caking agents. It will make a crystal clear saline solution.
Morton Salt and a couple of other companies make it. You can usually find it in the better grocery stores in their canning supplies section.
Be sure to use distilled water though.
As others have mentioned, you can use premixed sterile saline solutions. Just be sure they don't have preservatives or other additives in them. They can usually be found in the 'Eye Care' section of any drug store or grocery store.