Here is a list of salts and their property specs.
Posted in ReefCentral
Here is a list of what I measured for the big three in a number of the salt mixes we use today. This is intended as a guideline and I, in no way, guarantee these figures. All I can say is they were all tested under the same conditions, with a number of different brand test kits, using the same methods for each test. I believe these numbers are reasonably what you can expect from these salts mixed at 35 ppt or 1.0264
A special thanks to Bertoni for putting it in nice form.