This may seem like an odd article, but most beginners forget to ask their local pet store how to mix saltwater as they are more concerned with other set up questions. Then they get home and can’t figure out how to mix saltwater as the directions on the salt mix are not always easy to understand.
1. Start by purchasing a brand name saltwater mix like Instant Ocean, Reef Crystals, Coralife, Oceanic or Tropic Marin. Most salts made in the United States are actually manufactured in the same factory and are very similar. They will differ slightly in quality and consistency. Don’t use softener salt or cooking salt as these do not contain trace elements and other chemicals to help balance pH and alkalinity.
2. Buy a clean food grade mixing container; this can be a bucket, garbage can or plastic container. Only use this container for mixing saltwater to avoid contamination. It’s a good idea to write, “Fish Aquarium Only” on the plastic container with permanent marker.
3. Fill the container with water, preferably Reverse Osmosis water as it will have less iron, chlorine, nitrate, phosphate and other dissolved organics.
4. Add approximately 2 to 2 1/2 cups of salt per 5 gallons of water to make saltwater with a specific gravity between 1.020 and 1.026. If you buy salt mix in a bucket, the average container holds 5 gallons of water. After you use up the salt, the bucket makes a good, safe mixing container. Specific gravity is a measurement used to determine the salinity of water. Natural seawater is approximately 1.026, but a lower specific gravity can help reduce parasites in a fish only aquarium. If you plan to keep corals or invertebrates the ideal salinity is 1.024 to 1.026. Remember to always add salt to water, never add water to salt, as it may cause the calcium to precipitate out of the water.
5. If you are using a Refractometer mix the salt to the desired specification. If you are using a Hydrometer, mix the salt .003 lower than the desired amount. Hydrometers have a tendency to give false lows because they are not calibrated to take into consideration temperature. For example, a hydrometer reading of 1.020, most likely has a specific gravity of 1.023. It is normal for the saltwater to be cloudy, but it should clear after a few minutes.
6. Use a small pump or powerhead, like a Maxi-Jet 1200 to mix the saltwater for at least 24 hours. This will help balance the pH and ensure the saltwater is fully oxygenated. Also heat the water to approximately 78 degrees.
7. After 24 hours you may notice some small particles have settled on the top of the water, remove these with a Brine Shrimp Net Recheck the salinity and make adjustments if necessary. Remove the heater and powerhead. The water is now ready to use in your aquarium.