This was taken from another forum: I have switched to RNS and have done 3 water changes of 20% each every 2 weeks.
The dissolution rate of the RNS salt was very good with almost no residue left behind and parameters seem very reasonable. After checking the water-salt mix using Salifert test kits, I got the following:
Calcium 400 ppm
Magnesium 1300
dKH 9
Thats a slight difference from what Royal Nature advertises, but as many people are aware our test kits are not exactly the most acurate and a slight difference in the salinity or slightly off testing could be the cause for the values being approx off by 3-6%. Either way its pretty much exactl what we expected.