for me salt is salt. i am not worried about what are the levels on the water i am going to use for water change. i am more worried on what my tank water levels is at? no matter how much you keep the levels on your new water match to your tank it will still never be the same as soon as you add this to the display. the reason i said this is this, let's say you have a 100 gal total water volume and do a 30% water change, and you make your new water the same level as to your tank then do the water change. when you test your tank after the change let's say after a day, i bet yous it will be a different reading as to your original reading before the maintenance. so why bother adding supplements to the new water when you are still going to add supplement to the tank after a day or two. this is JMO basing on my own experience. you may have different take on this but hey what do i know, i am no expert, i just stayed at the holiday inn last night. :)
and as for the test kit. i prefer API over salifert. easier to use and IMO they give you the same reading and cheaper too.
