Mixing up a batch of saltwater is not difficult. Some marine aquarists enjoy the process. Others… not so much.
No matter how you feel about mixing saltwater, producing consistent batches of saltwater is important. Let’s explore several time-tested techniques that will make mixing saltwater easier and more consistent every time.
1) Select the proper salt mixing container
Most marine aquarists use an empty five-gallon salt mix bucket to blend seawater. If you only need a few gallons at a time, a bucket or two will work fine. If you have multiple aquariums or a large reef tank, consider a larger plastic drum. You’ll be able to make enough saltwater in one batch, save time and eliminate the hassle of mixing salt in multiple buckets. Never use a bucket or mixing container with a questionable history. Ideally the container should be new and never used for anything but mixing saltwater.
2) Use warm water to dissolve aquarium salt mix
Using ice-cold water to blend saltwater can slow the dissolving time a little bit. But more importantly cold water can shock your fish and inverts. Ideally the freshwater used to blend the salt is around 65-70°F. Avoid using hot water, however. Really hot water causes calcium to form insoluble calcium carbonate. A submersible aquarium heater can be used to slowly warm up the water and speed the dissolving process. If you are making and storing saltwater, keep it in a warmer part of your home, especially in winter. A garage or basement can chill the water. A submersible heater will keep the saltwater warm and always ready to use.
3) Reduce mixing time with a powerhead
Marine salts dissolve faster and more thoroughly when added to circulating water. Synthetic sea salt is a blend of chemicals with different dissolving rates. Circulating water keeps the particles suspended in the water and forces them to dissolve more quickly and evenly. If the marine salt is just dumped into the mixing container it settles on the bottom and resists dissolution. Use a submersible powerhead, like the Marineland Maxi-Jet Pro, to circulate the water in your mixing container.
4) Use a hydrometer or refractometer to check salinity
Follow the salt manufacturer’s directions for the amount of salt to use per gallon of water. Once the salt is fully dissolved, check the specific gravity with a hydrometer. Hydrometers measure the density of a liquid. Pure water has density or specific gravity of 1.0. As salt is added the liquid becomes denser and the specific gravity increases. The specific gravity of saltwater should fall in the range of 1.023-1025. Aquarium “swing arm” hydrometers are manufactured to measure specific gravity of saltwater at a specific temperature range. The Instant Ocean SeaTest Hydrometer is calibrated to work at 68 – 85°F.
You may also want to consider the Marine Depot Pro Aquarium Refractometer. A refractometer is an optical device that measures specific gravity and salt concentration (salinity) in parts per thousand (ppt). Natural seawater has a salinity of 35 ppt. Using a refractometer is quick and easy. Just add a few drops of saltwater onto the refractometer and read the level through the eye piece. Refractometers are considered more accurate and easier to use than hydrometers.
5) Keep all of your salt mixing gear in one place
Keep the dissolving pump, hoses, heater and other gear all together in one place. Label the salt mixing container so it does not get borrowed to wash the car. This way you won’t have search through the house, basement and garage looking for your equipment. To make things easier, we’ve put together the D-D H2Ocean Magnesium Pro Plus Saltwater Mixing Kit. This saltwater mixing kit contains everything you need to quickly mix up saltwater for your marine or reef aquarium.
- D-D H2Ocean Magnesium Pro PLUS Salt Mix (makes 43-52 gallons of saltwater)
- 1/2″ diameter Tubing (10 ft)
- 200 watt Heater
- Portable Refractometer
- Maxi-Jet 1200 Pro Powerhead
- Digital Thermometer
What advice would you give to a new hobbyist who wants to mix saltwater for their first time? Any equipment or salt mix recommendations? We would love to hear your thoughts in the comments below!