What is the proper way to mix salt water?
Always add the salt mix to the water, not the other way around. Adding water to the salt mix briefly creates a highly concentrated solution that can lead to precipitation of some ingredients. Always allow newly mixed salt water to circulate with a powerhead or airstone at least overnight before use. This allows the carbon dioxide in the aquarium water to reach equilibrium with the carbon dioxide in the atmosphere, which normalizes pH. It also adds oxygen.