Thanks everyone. ccCapt, I will go with your advice, you seem very knowledgeable on the subject and it makes sense to me. Like everything in this hobby, so many different opinions on every topic. I read somewhere else that you should use calibration fluid, but the directions say to use distilled water. Also a rep from Foster&Smith told me to use distilled water (with the one I had to return though, a different brand).
Nomadu571, I think you are referring to a hydrometer, I have heard that you should leave saltwater in those for 24 hrs before use.