How to Mix your Tanks Salt Water
Not only do you need to mix your saltwater before filling your tank the first time, but you will also need a supply of saltwater on hand for performing weekly water changes. Unlike freshwater aquariums, you cannot simply squeeze in a few drops of aquarium water conditioner and then dump the new water directly into the tank – to perform a water change in a saltwater tank you need to prepare the saltwater the day before. Because you will be mixing saltwater on a regular basis it would be wise to create a mixing container designated specifically for mixing saltwater. Depending how much water you need, this container could be as large as a 50-gallon trash container. In addition to the container and the salt mix, you will also need a powerhead to aerate the water, a heater to heat it and a thermometer to monitor the water temperature — to measure the salinity of the water you will also need a refractometer or a hydrometer.
To mix your saltwater, fill the container with fresh water and place the powerhead and the aquarium heater in the bottom of the container to help the salt dissolve more quickly. Next, mix in the amount of salt mix recommended on the salt mix container – divide the amount into thirds and mix in one third, letting it dissolve completely before adding more. After the salt has dissolved, check the temperature of the water and calibrate your refractometer or hydrometer accordingly. Measure the salinity of the water and make any necessary adjustments by diluting the water to lower the salinity or adding more salt to increase it. Once you have achieved the desired salinity, cover the container and let the powerhead run for several hours (ideally, 24 hours) until you are ready to use it.