The best salt is the salt that closely matches your parameters. I prefer to run 450 calcium, 9 alkalinity and 1350 magnesium. That’s why my preferred salt is tropic Marin pro because it’s almost exactly that. Many people run successful tank with instant ocean as well, it’s truly preference. But to best answer your question is to figure out the parameters you want to run then find a salt that mixes as close to it as possible.