Determination of salinity in your reef tank with SmartRef Digital Refractometer

Measuring salinity in reef tanks is crucial for any saltwater aquarium owner. Learn what to consider when taking measurements and how best to proceed.

A saltwater aquarium brings a piece of the mysterious sea into your home. Watching beautiful fish, invertebrates, and corals can have a positive impact on your well-being and reduces stress. Therefore, marine livestock nowadays counts as one of the most popular pets worldwide.

Salinity in reef tanks:

If you have decided to introduce such a lovely hobby into your life or if you are already a happy owner of a saltwater aquarium, you need to provide a natural and healthy environment for your marine dwellers. In order to achieve this, the aquarist needs to know certain values, like temperature, light, pH, and more.

One of the most important parameters an aquarist needs to consider is the saltwater salinity. The salinity or salt water content describes the concentration of dissolved salts in water. This parameter averages at around 35 ppt (parts per thousand) or 1.026 SG (specific gravity) for natural seawater. Therefore, this value is most often used for marine aquariums. In general, it is said that saltwater tanks with fish only can have a lower salinity than reef aquariums because fish accept lower salinity than corals.

Why do I have to measure the saltwater aquarium salinity?

Marine fish can’t survive in water with too low salinity levels, because their bodies contain a high concentration of salt solution. On the other hand, too high-salinity levels cause stress for the fish, because they need to implode their osmoregulation system to protect themselves from the high salt content in the tank.

Incorrect salt levels in the aquarium harm the sea inhabitants and can lead to death... As this is the worst scenario an aquarist can imagine, it is recommended to keep an eye on the salinity in your reef tank. Frequent measurements allow you to react quickly when salinity changes and avoid major impacts on marine life.

How often do I need to measure the salinity in my saltwater tank?

It is recommended to check the salt content of your aquarium on a regular basis. In general, it is important to measure the salinity of the first mixture and when doing water changes.

BLENDING SALT IN WATER:

The first time you need to check the salinity is when you blend a new saltwater for your reef aquarium. The manufacturers of the salt mixture usually specify how much salt is needed to achieve the desired salinity. Ideally, you should use reverse osmosis water or distilled water for dilution, to avoid impurities in the tank. Once the sea salt is fully diluted in the water, you need to check the salinity to determine if the desired salinity has been achieved or if you have added too much or too little sea salt to the water. It is recommended to repeat the measurement over the next few days to verify that the salinity doesn’t change before welcoming your tank dwellers to their new home.

WEEKLY SALINITY MEASUREMENTS:

Once a stable salinity environment for your tank dwellers has been achieved, weekly measurements should be performed to verify that the salinity level is within the optimal range. This is necessary because water evaporates daily and the salt ions remain. As a consequence, the salinity level increases.

WATER CHANGE:

Most aquarists perform a 10 to 20 % water change every one to two weeks to remove waste products from the inhabitants and maintain the nutrient levels in the reef tank. To make the water change as relaxed as possible for your marine livestock, the salinity of the saltwater must be measured before it can be added to the aquarium. This is because a rapidly changing salt content in the aquarium leads to high stress levels for the tank dwellers, which you want to avoid.

Checking the salinity with SmartRef digital refractometer:

Now it’s easier and faster than ever to keep an eye on the salt content of your saltwater tank. The digital refractometer SmartRef with the Reef Meister mobile app supports you at each step when you have to check the saltwater salinity.

All you have to do is to take a 0.4 mL sample of your aquarium and the SmartRef with the Reef Meister mobile app will give you the temperature-compensated result for the salinity in ppt, PSU, and specific gravity in seconds. With a single tap, the result can be directly saved in corresponding projects.

To verify that the salinity level in your marine aquarium is constant you can graphically follow the history of the values over time. This helps you to quickly check the consistency of the salinity and alerts you at a glance if you need to take action.