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Natural Saltwater vs. Salt Mix: Which is Right for Your Reef Tank?

natural vs mix salt

Saltwater is an important part of keeping your aquarium healthy. It doesn’t matter if you have a fish-only tank or a reef tank, it’s crucial to understand the differences between natural saltwater and salt mix. This knowledge will help ensure the well-being of your aquatic pets. While some people may think that natural saltwater from the ocean is the best choice, many aquarium owners prefer to use salt mix instead. There are advantages and disadvantages to both options, but first, let’s try to understand the composition of saltwater itself.

Seawater Composition

The six most common ions found in seawater are chloride (Cl−), sodium (Na+), sulfate (SO24−), magnesium (Mg2+), calcium (Ca2+), and potassium (K+). Together, these ions make up about 99 percent of all sea salts by weight. The amount of these salts in seawater can vary due to local factors such as precipitation and evaporation. The salt content in seawater is measured by salinity (S), which is defined as the amount of salt in grams dissolved in one kilogram of seawater and expressed in parts per thousand. Salinities in the open ocean typically range from about 34 to 37 parts per thousand (0/00 or ppt), which can also be expressed as 34 to 37 practical salinity units (PSU). Marine aquariums are also measured using a metric called specific gravity. Specific gravity is the comparison of a liquid’s density (in this case seawater) to the density of pure water. Since the density of a liquid changes with temperature, the specific gravity also changes. It has been determined that liquids with a specific gravity less than 1 are lighter than water, while those with a specific gravity greater than 1 are heavier. In the case of seawater with a salinity level of 35 parts per thousand (ppt), the specific gravity is 1.0236 at 25 Celsius Degrees.

For a marine aquarium, it is recommended to maintain a specific gravity range of 1.020 to 1.026. However, for a brackish aquarium, the recommended range is 1.005 to 1.015.

Among the minority elements, there are trace elements that are found in concentrations below 3 mg/L. These elements, such as vanadium, cadmium, iron, molybdenum, zinc, lithium, cobalt, iodine, barium, lead, chromium, aluminum, gallium, copper, and cobalt, exist in even lower concentrations. Some of these elements play a crucial role in the metabolic processes of many organisms. However, it’s important to exercise caution as excessive accumulation of these trace elements beyond the recommended levels can be highly harmful.

Saltwater plays a vital role in creating a suitable habitat for marine life in your aquarium. It provides various benefits that contribute to the overallwell-being of your aquatic pets:

Nutrient Transport

Saltwater plays a crucial role in facilitating the transportation of essential nutrients within the aquarium. It effectively transports vital minerals, trace elements, and other necessary nutrients to support the growth and development of marine organisms. Thanks to the presence of saltwater, these organisms are ensured the proper nourishment they need to thrive.

pH Stability:

Saltwater plays an essential role in preserving the equilibrium of your aquarium’s pH levels. By acting as a natural buffer, it effectively prevents any sudden shifts that could potentially harm marine life. Ensuring a stable pH is of utmost importance as it directly impacts the overall health and well-being of your aquatic pets.

Disease Prevention:

Saltwater possesses inherent antiseptic properties, which effectively combat diseases within your aquarium. By aiding in the maintenance of water quality and minimizing the likelihood of bacterial and fungal infections, saltwater plays a crucial role in safeguarding the health of your aquatic pets. Ensuring the appropriate composition of saltwater further contributes to the overall well-being of your marine companions, bolstering their immune system and promoting optimal health.‍


Differences Between Natural Saltwater and Aquarium Salt Mix

When it comes to providing saltwater for your aquarium, you have two options: natural saltwater or salt mix. Here are the 10 key differences between the two:

1. Composition

Natural saltwater is obtained directly from the ocean and as we mentioned before contains a balanced mix of salts, minerals, and trace elements naturally found in the ocean. On the other hand, salt mix isa commercially available product that requires you to mix it with freshwater to create artificial saltwater. Salt mix is carefully formulated to mimic the composition of natural seawater.

2. Consistency

Natural saltwater is subject to natural variations in composition, depending on factors such as location, season, and time of collection. This can result in inconsistent parameters, making it more challenging to maintain stable conditions in your aquarium. Salt mix, on the other hand, provides a consistent and predictable composition, ensuring stable water parameters for your marine pets.

3. Control and Customization

With natural saltwater, you have limited control over the precise composition and quality of the water. This lack of control can make it more challenging to fine-tune and adjust the water parameters to meet the specific requirements of certain sensitive marine organisms.

4. Availability and Convenience

Natural saltwater is not readily available to everyone, especially if you don’t live near the coast. Collecting or purchasing natural saltwater can be time-consuming and inconvenient. Salt mix, however, is widely available and can be easily obtained from local aquarium stores or online retailers.

5. Ease of Use

Unlike salt mixes that require measuring and mixing, natural saltwater is ready to use right away. This convenience can save you time and effort when setting up and maintaining your aquarium, allowing you to spend more time enjoying your underwater oasis.

6. Risk of Contamination

When utilizing natural saltwater in your aquarium, there is a potential risk of introducing unwanted pests, parasites, or diseases. To address this concern, it is important to implement proper quarantine measures and exercise caution when selecting the source of your saltwater. By taking these precautions, you can effectively mitigate the risk associated with introducing these potentially harmful elements into your aquarium.

7. Artificial Composition

Salt mix is formulated to mimic the composition of natural seawater, but it is still an artificial product. Some purists argue that natural saltwater contains a more diverse and complex range of beneficial microorganisms and bacteria that contribute to a healthier ecosystem.

8. Storage and Shelf Life

Salt mix must be stored correctly to maintain its quality and effectiveness. Improper storage conditions, such as exposure to moisture or extreme temperatures, can lead to degradation of the product. Additionally, salt mix has a limited shelf life, and using expired mix can have adverse effects on your aquarium.

9. Initial Investment

While salt mix can save money over time, there is an initial investment involved in purchasing the mix and the necessary equipment for mixing. However, this cost is generally offset by the long-term savings and convenience of using salt mix.

10. Formula

Not all salt brands are identical. There may be differences in the levels of the main components. It is crucial to understand the specific requirements of your aquarium in order to select the most suitable option.


Our Top Choices

In our view, there is no perfect or best brand. The ideal choice depends on the type of aquarium you have. If it’s a fish-only-with-live-rock (FOWLR) or a Reef Tank, and within those, if you have mostly LPS, SPS, or Soft Corals. However, when selecting your Salt Mix brand, you should also consider factors like your budget, mixing time and levels of Ca-Kh. Taking into consideration all of these factors, these options are our top choices:

Tropic Marin Pro Reef:

Tropic Marin is a leading brand in the market. Their Mix Salt is made from pure salts, without any artificial additives. It contains all 70 trace elements that are naturally found in seawater, making them biologically beneficial. These salts have been tested and proven to have effective formulas, high-quality ingredients, and are meticulously manufactured to ensure optimal solubility in water. Tropic Marine pro Reef restores the proper ionic balance in your tank while also maintaining ideal pH levels for a healthy reef aquarium.

Red Sea Salt:

The Red Sea Salt Mix is widely preferred due to its fast blending capabilities and comprehensive blend of essential elements found in natural seawater, perfectly balanced for a mixed reef tank. What sets Red Sea salt apart from others is its distinctive design, enabling it to be effortlessly mixed and utilized within a matter of hours.

Red Sea Coral Pro Salt:

Coral Pro is a remarkable salt that can significantly enhance the growth of corals. In fact, it can increase growth up to four times the natural rate.This makes it an excellent choice for mixed reefs and SPS frag tanks, as it provides the necessary nutrients for optimal development. One of the stand out features of Coral Pro is its Alkalinity level of 12 dKH, which ensures the perfect conditions for coral growth. Moreover, this product is incredibly convenient to use, requiring only around 20 minutes to go from bucket to tank.This streamlined mixing routine saves you time and effort, allowing you to focus on enjoying your thriving coral ecosystem.

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About the author

Picture of Ana M.López

Ana M.López

Ana holds a degree in Marine Sciences and has completed a Master's Program in Aquaculture with a specialization in ornamental species. Additionally, Ana is a certified Dive Master and Cave Diver, taking her passion for marine life to new depths. Ana has gained years of experience in the aquarium industry.