Doesn't sell anything. HA. The S-15 report sells itself and the salt made by the people who are giving you the report. Sort of a one sided report. Problem is no one has really done any other studies since then. I'm not calling it completely faulse, as there are several salts that I can agree on from personal experience.
I will warn you about this. Any salt can have problems. Any production line can have screw ups. It is an awful thing to have your trusted salt nearly wipe out your tank.
If you make a water change and you see nothing but a cloudy mess in your mixing container then I would test the water change before use.
If your salt works for you then all is well. If your salt seems to be lacking then you should think about finding another one and see if you can get better results.
Instant Ocean is a great salt, has been for years, but I have recently stumbled on a bad batch. The company and I are now having an extended talk.
For those who use Instant Ocean, most of you aready know that it mixes and clears really soon. After mixing it should be clear in just a few minutes. IF IT DOES NOT CLEAR in a few minutes then I would test it before use. If it FOAMS up on the surface then I would test before use.
If any salt you mix does these things then it should be suspect, and tested before you transfer it to the main tank.
Thats all I got to say about that
Thomas