a little more on this. each brand mixes to different parameters. Alkalinity is the most important. So ask yourself what dkh do you want to maintain for your tank? There is no right or wrong answer as long as you are in the 8-12dkh range. Some ULN SPS tanks like to target the low end (even lower than 8). High ALK , high nutrients and high light is often associated with high growth tanks. You will often read that stability is more important than the actual number when it comes to alk.
me. I like anything between 8 and 9. I like to use the Red Sea mixed reef suggested parameters which are closer to 11 and even with reef crystals, my tank would never get that high, so I went with what my tank told me it likes to settle.
And, test your saltwater before adding to the tank. You want to match salinity and temperature and know what ALk and Ca are before adding to your tank (at least initially