Best Reef Salt Mix – Selecting the Best Salt for Your Tank

All budding reef tank enthusiasts (also known as “reefers”) share one common passion: discussing which salt mix provides the optimal environment for reef tank growth. The opinions are very divisive, and the discussions quickly become emotionally charged and unproductive.

The truth is, finding the best reef salt mix is a combination of science, experience, circumstances, and trial and error. 

Most reef aquarium salt mix manufacturers brag about the quality of their mixes, superior balance of calcium and alkalinity, and top-notch trace elements.

In reality, most of the premium-brand marine salt mixes are high-quality products that have pros and cons. But what suits one tank best, might be a poor fit for another.

In this guide, we will explain the facts about what are, in our opinion, the best reef salt mixes on the market and give you our recommendations.

Choosing the Best Reef Salt Mix for You

The first thing to understand is that the perfect reef salt mix for your tank is a personal preference.

The type of aquarium salt mix you will use in your tank depends on the size of your fish tank, the type of coral you are using in it, and the species of fish you are keeping. However, you are probably going to find several competing products that fit within all of these parameters.

This is where your own personal experience and preferences come into play. What is your budget? What is the ideal balance of calcium and alkalinity you are looking for?

These are just some of the questions that might help you choose. More likely, you will go with a brand that you are comfortable with or had a positive experience with in the past.

Remember, the perfect aquarium salt mix does not exist, and even the best ones are not always optimal for everybody’s needs.

Natural vs. Synthetic Salt Mix for Reef Aquariums

All reef salt product are either mined (natural) or synthetic. Natural or mined marine salt is a byproduct of mined evaporated seawater ocean deposits. As such, mined salt mixes have the distinct characteristics of the mined area but can often show variance in the content and major ingredients.

Reef salt mixes that are 100% synthetic or majority synthetic have a more controlled production process, stability of ingredients, and are some of the most expensive mixes on the market. Manufacturers can also infuse those mixes with other trace elements that they believe will improve the quality of the mix and its effect on the water in your tank.

Reef Salt Mix Major Elements

All reef salt products in the market consist of hundreds of unique elements. Yet, when it comes to choosing the right salt reef mix for your aquarium, there are three major elements that you have to keep in mind:

  • Calcium – Calcium is the building block of the coral reef, and without it, the coral will not be able to expand its skeleton and grow. Biomineralization is the process which enables the coral to use calcium and create a hard skeleton from it. Ideally, marine salt mixes should contain around 400ppm of calcium. The more calcium there is in the mix, the lower the alkalinity of the water.
  • Alkalinity – Alkalinity of seawater directly relates to the pH levels in the water and the presence of bicarbonate. Stable pH levels in the tank and the presence of bicarbonates ensure that the coral can grow freely. As long as alkalinity is between 8 and 11, your tank should be fine for coral growth.
  • Magnesium – As the main catalyst that makes calcium interact with other trace elements to maintain alkalinity, magnesium plays an important role in keeping the tank water in perfect balance. The ideal magnesium levels range between 1,200ppm and 1,400ppm.

Best Salt for Reef Tanks

Fritz Aquatics Reef Pro Mix (Mined)Fritz Aquatics Reef Pro Mix (Mined)


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Instant Ocean Reef Crystals (Mined)Instant Ocean Reef Crystals (Mined)

10, 25, 50, 160, 200-Gallon

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Instant Ocean Sea Salt for Marine Aquariums (Mined)Instant Ocean Sea Salt for Marine Aquariums (Mined)

10, 25, 50, 160, 200-Gallon

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Red Sea Coral Pro Salt (Mined)Red Sea Coral Pro Salt (Mined)


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Brightwell Aquatics Neomarine Salt (Synthetic)Brightwell Aquatics Neomarine Salt (Synthetic)


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Fritz Aquatics 80280 Reef Pro Mix Complete Marine Salt (Mined)Fritz Aquatics 80280 Reef Pro Mix Complete Marine Salt (Mined)

50 Gallon

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Tropic Marin Pro (Synthetic)Tropic Marin Pro (Synthetic)


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Best Reef Salt Reviews

1. Fritz Reef Pro Mix

fritz pro

It seems that Fritz Reef Pro Mix is everywhere. From reefer forums to online retailers and reef enthusiasts, Fritz Reef Pro Mix certainly has strong brand recognition and great marketing. It has excellent availability as well, with countless online and brick-and-mortar retailers carrying the product (and often selling it for a discounted price).

This mix was the quickest mixing one we had a chance to review. It reaches optimal alkalinity levels very quickly and provides an excellent balance of calcium in the tank. Moreover, there are no caking agents present in this mix.

Yet, even this mix can hit a dead end, especially when it comes to hard coral, such as Acropora. It is better suited for LPS and mixed reef. Fritz Reef Pro Mix offers a perfect balance of quality ingredients, mixability, and price, making it our No. 1 choice.


  • Calcium – 400-450ppm
  • Alkalinity 8.0 – 8.5 DKH
  • Magnesium – 1,300 – 1,400ppm


  • Excellent balance of calcium and alkalinity, ideal for most tanks
  • Available in most local and online retailers
  • Excellent value for money when discounted
  • Perfect for those with LPS and mixed reef.


  • Expensive when at full retail price
  • Not suitable for Acropora corals

2. Instant Ocean Reef Crystals

crystals reef salt

Instant Ocean Reef Crystals is the best budget salt mix on the market. It is nearly impossible to miss, as it is one of the most popular reef salt mixes. It’s available in all the major retailers online, as well as pet supply stores.

The budget pricing of the Instant Ocean Reef Crystals does come with some drawbacks. With alkalinity of 13, this mix suits mixed reef and soft tanks best and might harm tanks with more sensitive coral. Additionally, anti-caking agents used in the Instant Ocean Reef Crystals can lead to a build-up of brownish crust on the tank walls, something that requires tedious cleaning.

Overall, Instant Ocean Reef Crystals is an excellent product for those on a budget, as long as you are aware of its limitations, and your tank fits its target profile.


  • Calcium – 490ppm
  • Alkalinity – 13 DKH
  • Magnesium – 1440ppm


  • Fantastic value for the price. The best budget reef salt mix
  • Excellent reputation and immaculate quality control
  • Easy to find in most retailers
  • High magnesium and calcium contents


  • Anti-caking agents create an unwanted build-up
  • High alkalinity harmful for more sensitive Acro-type coral
  • Suitable only for soft or certain types of mixed reef tanks

3. Instant Ocean Sea Salt

This is a big seller from Instant Ocean, a company with more than five decades of leadership in the industry. Instant Ocean Sea Salt is the most used sea salt product in the world. From huge public reef aquariums to hobbyists and enthusiasts, Instant Ocean Sea Salt’s quality and value speak for itself.

Taking that into account, Instant Ocean Sea Salt is not a perfect product. It performs best when used in fish-only tanks or fish tanks with live rocks or soft corals. It will not do well with hard corals, possibly even hurting them. The same issue that plagues Instant Ocean Reef Crystals persists here, the build-up of a tough brown residue that is tough to remove.

Still, being one of the most affordable brand-name sea salt products in the world with an unmatched track record and history in the industry, Instant Ocean Sea Salt is a great value even today. Many manufacturers have tried to beat out Instant Ocean Sea Salt with more innovative and quirky products, but Instant Ocean Sea Salt is still holding steady.


  • Calcium – 400ppm
  • Alkalinity – 11 DKH
  • Magnesium – 1,350ppm


  • Affordable
  • One of the quickest mixing salts
  • Perfect for fish-only or fish with soft coral tanks
  • The most popular sea salt on the market, available everywhere


  • Not ideal for hard corals
  • An issue with anti-caking agents (creates brown residue build-up)

4. Red Sea Coral Pro Salt

If you are looking for a saltwater aquarium mix that is 100% natural and perfectly mimics actual seawater conditions, then look no further than Red Sea Coral Pro Salt. The salt that goes into this mix comes directly from the Red Sea, so it’s no wonder that this is one of the highest quality mixes on the market.

Most frag sellers and SPS tank owners swear by the Red Sea Coral Pro Salt, insisting that it is the only solution available with stable alkalinity and balanced levels of calcium and magnesium conducive to SPS growth. It is also an eco-friendly product that does not use any harmful chemicals.

The only real downsides of this product are its price, which is not cheap, and its availability. It might be challenging to get your hands on one of these unless you have a specialty, marine supply store near you, or you order it online.


  • Calcium – 450ppm
  • Alkalinity – 12 DKH
  • Magnesium – 1340ppm


  • The best reef salt mix for SPS tanks
  • 100% natural, harvested salt from the Red Sea
  • Eco-Friendly
  • Firm quality control and brand reputation


  • Quite expensive
  • Difficult to get ahold of

5. Brightwell Aquatics Neomarine Salt

kent marine salt

Brightwell Aquatics is the brainchild of Chris Brightwell, the former owner of Kent Marine. The brand prides itself on its extensive research and testing (carried out in real-world marine environments) as the core part of their product development process.

Brightwell Aquatics Neomarine Salt is a product that most SPS tank owners will find appealing. Its low alkalinity is stable and conducive to SPS coral growth. Additionally, the alkalinity of this mix is not prone to spikes. Since this is not an evaluated alkalinity product, the alkalinity continuously sticks to 7.5 to 8.0 DKH. On top of all that, Neomarine Salt does not have any anti-caking agents and it dissolves quickly.

Similar to previously mentioned Red Sea Coral Pro Salt, the price tag is what turns most people off. The mix is priced as a high-quality product should be. Product distribution and availability are also an issue, although not to the level of Red Sea Coral Pro Salt.


  • Calcium – 413ppm
  • Alkalinity – 7.5 DKH
  • Magnesium – 1,290ppm


  • Perfect for SPS tanks, due to low alkalinity
  • No anti-caking agents
  • Endorsed by large coral dealers
  • Created by an industry veteran with marine experience


  • Expensive
  • Not readily available in retail outlets

6. Fritz Aquatics 80280 Reef Pro Mix Complete Marine Salt

Fritz Aquatics 80280 Reef Pro Mix Complete Marine Salt is one of the best all-around reef salt mixes available today. Whether you have a fish-only tank or you also keep different types of reef coral in the tank, 80280 Reef Pro Mix is up to the task.

Designed by marine specialists and professionals, 80280 Reef Pro Mix has gone through extensive testing, ensuring that it is safe for marine life. It is an ammonia-, phosphate- and nitrate-free product that is gentle on sea life. The product quickly mixes with aquarium water and reaches the needed pH level in no time. 

Although not a budget product, 80280 Reef Pro Mix is an affordable one and a great value, easily found in retail outlets.


  • Calcium – 450ppm
  • Alkalinity – 8.5 DKH
  • Magnesium – 1,350ppm


  • Excellent all-around marine salt mix
  • Balanced formula with enough calcium and magnesium for coral growth
  • Excellent for beginner hobbyists, just getting into reef tanks
  • Quick dissolving mix


  • There are better products out there for each tank type
  • Reef Pro has a shady quality control history

7. Tropic Marin Pro Reef Salt

tropic marin reef aquarium salt

If you are looking for the absolute best SPS tank salt mix and are willing to spend the necessary funds to get it, Tropic Marin’s Pro Reef Salt is the product you are looking for. A fully-synthetic blend—created with pharmaceutical precision of ingredients and elements—it delivers perfect conditions for SPS corals to grow.

Tropic Marin is the premium brand of marine supply products, particularly in Europe. The mix is ready out of the box and delivers instant performance, as it mixes quickly with the reef water. Water changes are not a cause for worry, as the alkalinity levels will remain stable and your fish and marine life will be safe and sound.

The price of all this might be astronomical for some, but the product targets enthusiasts that will spare nothing to get a perfect reef tank. On top of that, the product is not easy to find, and you either have to order it online or find it in a specialty store.


  • Calcium – 450ppm
  • Alkalinity – 8.5 DKH
  • Magnesium – 1,380ppm


  • The absolute best SPS tank reef salt mix on the market
  • High-quality, fully-synthetic salt mix
  • A perfect blend of ingredients that stimulates healthy growth
  • A renowned brand with decades of experience                                                                                                                                                             


  • Extremely expensive
  • Difficult to find in regular retail stores

Reef Salt Frequently Asked Questions (FAQs)

In this section, we will try to answer some of the most common questions you might have about reef salt mixes.

Where Should I Buy Reef Salt Mix?

Reef salt mixes are available in local brick-and-mortar marine shops and pet supply chain stores. Typically, you can purchase them in either small amounts or in bulk. The other option is online retailers such as Amazon or specialty retailers.

A lot of online pet and fish supply retailers have stopped carrying reef salt mixes, due to the inability to ship them efficiently and still turn a profit. High shipping costs seriously affect the bottom line for these companies. Therefore, only giants like Amazon can use economies of scale to make a profit.

How Do I Mix Saltwater for My Aquarium?

Mixing saltwater for the tank sounds way more complicated to beginners than it really is. Once you have done it a few times, the process will feel natural and comfortable.

It all starts with a RODI (reverse osmosis deionization) system you will use to prepare your saltwater, along with a refractometer and a 35ppm calibration fluid. Pay close attention to the water temperature, because you want to perform all the measurements as close to the ideal water temperature as possible using an aquarium heater.

After the water is at the ideal temperature, you turn on a return pump or wavemaker and start adding salt according to the instructions of the reef salt manufacturer. You are aiming for a 35ppm (or 1.026) concentration. Whenever you add salt, make sure to wait for 30 minutes before taking salinity measurements. Some reefers prefer to leave the mix overnight and take measurements in the morning before changing the water.

Now you know how to mix saltwater.

Which is the Best Reef Salt to Use?

This question does not have a simple answer. The saltwater aquarium salt will vary depending on the type of tank (fish-only, fish with live rocks, SPS/LPS reef tank, or mixed reef tank) you have, as well as the type of marine life in it.

How to Choose Reef Salt Mix for Your Reef Aquarium?

There are several factors you have to consider when choosing the right marine salt mix for your aquarium:

  • Ingredients (the big three are calcium, magnesium, and alkalinity)
  • Per gallon cost of the mix
  • Type of tank and marine life in it
  • Brand reputation and quality control

Make sure that you carefully read the ingredients of all reef salts you are considering and that they match the requirement of the reef you have in your tank. Stable, low alkalinity is crucial for coral reef growth, as well as the abundance of calcium and magnesium.

The cost of the mix is essential. Premium brands and products can set you back a hefty sum, so finding the optimal combination for your budget is crucial. Finally, stick to the brands with a proven track record and dedication to research, testing, innovation, and quality control.

How Much Salt Per Gallon for Reef Tanks?

The amount of salt per gallon for reef tanks depends on the type of tank, the marine life in it, and the marine salt mix brand requirements. So, make sure to follow the instructions provided by the manufacturer closely. On average, 35 grams of mix per liter, or 132 grams per gallon, is the ideal mix for reef tanks.

Our Recommendations for Reef Salt Mix

Ultimately, the type of coral you would like to keep determines your reef salt mix. This list can act as a quick reference regarding the products we mentioned and what makes them a great buy:

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Kelly Stanley