But the levels of those with the lower salinity would be higher. For example, Kent is between 29 and 30 ppt, while Red Sea Coral Pro is between 33 and 33.5.
The average silica for the above is 0.55 and 0.8 respectively, apparently indicating that Kent has lower silicate, but once you add more of the Kent salt to the water to bring the salinity up to a level near NSW, then the level of silica in the water will rise too.
There will not be a great change, but it would certainly be more useful for aquarists to see comparisons witht he salt concentrations at levels used in the tanks. How many people who care about magnesium will put in salt at 29ppt?