5 Best Reef Salt Mix Options [Review & Buyers Guide]

Reef salt mix is a critical addition to any aquarium. We all have those little comforts that make our home feel like home, right?

Like how it doesn’t truly feel like home until you have a candle on, or until you turn your fairy lights on.

It’s the same for aquatic life. They have their own important features that they need in their homes to make it habitable for them.

One of these is reef salt. Reef Salt is the substance that makes aquarium water like their natural habitat.

It contains nutrients that make regular tap water suitable for them to live in by adding important calcium, magnesium, and much more.

Whilst candles and fairy lights are an important part of our homes that makes us feel comfortable, and they are not something that we cannot live without.

For your aquatic life, this is not true. They need this reef salt mix to thrive and survive. It is, therefore, of utmost importance that you get this right.

To help you make the best decision for your aquarium’s reef salt mix, we have decided to put together five of the best reef salt mixes we have found, reviewing each of them with a pros and cons list.

As well as this, we have given you a Buyers’ Guide to inform you about reef salt mixes and the important features you should look for when buying your mixes. 

So if you are about to get your first fish tank and are looking for the perfect reef salt mix for it, look no further because this article will give you all the information you could need. 

Top Pick – Instant Ocean Sea Salt for Marine Aquariums

If you are in a hurry to get your fins on the best reef salt mix, there is, look no further than Instant Ocean’s Sea Salt for Marine Aquariums. We love this stuff. Find out why:

  • A great choice for tanks that have fish and soft corals 
  • Contains all of the important trace elements your tank could need to make it feel like natural seawater 
  • It dissolves quickly and easily, producing a clear solution 
  • It is also a good choice if your aquarium has invertebrates like hermit crabs 

Pick up a pack of it today on Amazon – Instant Ocean Sea Salt for Marine Aquariums


Quick List Best Reef Salt Mix

  1. Instant Ocean Sea Salt for Marine Aquariums
  2. API Aquarium Salt
  3. Instant Ocean Reef Crystals Reef Salt
  4. Red Sea Fish Pharm Coral Pro Marine Salt for Aquarium
  5. Brightwell Aquatics NeoMarine – Marine Salt Blend for Reef Aquarium

Top Pick: Instant Ocean Sea Salt for Marine Aquariums

Instant Ocean Sea Salt (50 gal)_MB

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The top of our list just had to be this product by Instant Ocean. They are a brand with over 40 years of experience, so you know you are in the hands of experts.

Their Sea salt for Marine Aquariums mix is a great choice for tanks with fish and soft coral.

It is less appropriate for hard corals, though, so do bear this in mind. It is formulated with marine life in mind and contains all trace elements that your fish and invertebrates could need.

It is fast dissolving and gives a clear solution ready to use in minutes, so you need not worry about any color alterations.

There are also no unnecessary additives in this salt mix, so you can rest assured that it will not upset your aquarium’s delicate balance. 


  • An amazing choice if your tank is a fish only tank or if you have fish, invertebrates, and soft corals 
  • It is an ‘instant ocean’ in a box, as the product name suggests. Your aquarium inhabitants will thank you for making it as close to their natural habitat as possible. 
  • It dissolves easily to a clear solution. 
  • It is also a great choice for hermit crabs that may be in your tank. 


  • This is not suited for hard corals in your tank. If you have a tank with hard corals, you will need something targeted towards them. Try one of the other reef salt mixes on our list! 

Second Pick: API Aquarium Salt

API AQUARIUM SALT Freshwater Aquarium Salt 65-Ounce Box

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Our list is off to a fin-tastic start thanks to this excellent runner-up. API’s Aquarium salt. This electrolyte rich Aquarium Salt is an ideal product choice for someone keeping a fish only tank.

It is made from evaporated seawater to get the conditions inside the tank as close to your finned friends’ natural environment as possible.

It can help to improve the gill function of your fish whilst reducing stress in all freshwater aquariums. It would be best to use it when setting up a new tank or having a water change in your aquarium set up.

As well as this, it can also be used to promote disease recovery for unhealthy fish in your tank. It can help to promote the uptake of oxygen in your fish.

It can help to dispel carbon dioxide and ammonia from your fish through their gills. 


  • Great for a freshwater tank with only fish within it 
  • It can help promote oxygen intake. 
  • Rids your fish of ammonia and carbon dioxide 
  • Provides the same important electrolytes and elements they would get in a natural environment. 
  • Great for overall tank health 


  • Not suitable for coral in your tank. Only use this in a fish only tank. 

Third Pick: Instant Ocean Reef Crystals Reef Salt

Instant Ocean Reef Crystals Reef Salt For 160 Gallons, Enriched Formulation For aquariums

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Yes, that’s right… yet another Instant Ocean product has made it onto our list. This time we have their Reef Crystals Reef Salty which is specifically designed with coral reefs in mind.

This is a great choice if you happen to have hard corals in your tank and be suitable for fish and soft corals. It can also support the growth of anemones and invertebrates.

It has elements from ocean reefs in far greater concentrations than natural seawater to ensure your tank is getting everything it needs.

It provides extra calcium, which is incredibly important if you have coral in your tanks.

It can also help neutralize trace heavy metals from tap water, making it the perfect aquarium environment for your finned friends. 


  • Suitable for all types of coral as well as anemones, fish, and invertebrates 
  • Boosts calcium in your tank, which is essential in promoting the growth of your tank life 
  • It dissolves quickly 
  • Available in four different sizes, including this one, which is a whopping 160 gallons, so you can stock up when needed 
  • It keeps well once opened. 


  • It can sometimes leave a residue even after it has dissolved thoroughly. 

Fourth Pick: Red Sea Fish Pharm Coral Pro Marine Salt for Aquarium

Red Sea Fish Pharm ARE11220 Coral Pro Marine Salt for Aquarium, 55-Gallon


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Red Sea Fish Pharm has specially formulated a product with coral reefs in mind. Their Coral Pro Marine Salt for Aquarium mix is ideal to meet the needs of advanced coral keepers.

It can be used with soft tap water and contains the perfect calcium levels to keep your coral happy.

Whether you have hard or soft coral, this product promises that you will see vibrant coral growth. It is also great for reverse osmosis users.

It is balanced enough to support even the most delicate of coral and other aquatic life such as algae and invertebrates as it helps them build up their shells and skeletons.

It also ensures salinity levels are kept at the place they need to be. 


  • It is quick to dissolve and does so very clearly, so you need not worry about watercolor alterations. 
  • It has immediate positive effects on your tank life. 
  • Encourages coral growth as well as the growth of shells and skeletons in your marine life 
  • It gives excellent levels of calcium in your tank. 


  • One major downfall is the packaging it comes in. not everyone has experienced problems. However, quite a few have had their buckets arrive damaged, causing them to have to decant the mix into another container, so it keeps well. 

Final Pick: Brightwell Aquatics NeoMarine – Marine Salt Blend for Reef Aquarium

Brightwell Aquatics NeoMarine - Marine Salt Blend for Reef Aquarium

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Everyone knows that a great and successful aquarium begins with excellent quality tank water. It provides all of the trace elements your tank may need to stay healthy and keep thriving rather than just surviving).

It is ideal for all marine organisms, rather than just fish. It replicates natural seawater, so your tank feels as close to home as possible for its inhabitants.

It mixes within a few hours to an obvious solution, dissolving completely. It is also free of any harmful phosphates, ammonia, nitrates, and other organic substances that can cause your tank, and anything in it, harm. 


  • It is very clean and uniform on mixing. 
  • It has all the right trace elements that your tank needs to stay healthy. 
  • Promotes coral growth 
  • The instructions are detailed, so you know exactly how to use it. 


  • Some people have found that the levels of calcium and magnesium have been too low for their needs. 

Best Reef Salt Mix Buyers Guide

When buying reef salt mixes, there are several factors that you should take into consideration to make sure that you purchase the correct mix for your aquarium.

In this Buyers’ Guide, we will explain each of these factors for consideration to you, explaining how important it is to get it right. Consider each of the factors before you purchase anything. 

Natural Elements – Magnesium, Calcium, and Alkalinity

These three natural elements, sometimes known as the Big Three and essential to get right.

They are found naturally in saltwater (along with salt, of course) and are needed in your aquarium for your aquatic life to adapt to it.

Calcium is important, especially if you have coral and invertebrates in your aquarium.

This is because it helps them strengthen their skeletons, giving them strength, almost as it does for our bones and teeth. Really, aquatic life isn’t that far from human life.

Magnesium adds alkalinity to the tank, and although it is not found in natural saltwater in vast amounts, it is still a critical feature.

It is so important because it helps to balance out the alkaline levels to keep it perfect for your tank.

Lastly, it would help if you considered the alkalinity of the tank in general. Without having a high enough alkaline level, the water in your aquarium will be too acidic.

It may even be acidic enough to dissolve coral and kill your fish. 

Therefore, it is essential that the reef salt mix you choose for your tank to have these natural elements.

It would help if you only chose a reef salt mix that assures you that it includes these. 

What’s in your tank? 

Consider the life of your tank carefully. Different aquatic life forms have different needs.

As well as this, different reef salt mixes have different levels of the natural elements that we discussed in the previous section.

For example, fish have slightly different needs and preferences from coral, especially hard coral. Soft coral has similar needs to fish.

Depending on what is in your tank, you may want to consider a reef salt mix with extra nutrients and vitamins suited to your particular aquatic life.

The most important consideration when it comes to factoring in what is already in your tank is the levels of alkalinity.

Ideally, hard corals will be in slightly higher alkaline levels. On the other hand, soft coral and fish will need lower levels. 

Coral, in particular, needs careful consideration. This is because they tend to use a lot of calcium and magnesium to build their skeletons as they grow and live.

This means that having hard coral may slightly deplete your overall calcium and magnesium levels, as well as having an effect on other vitamins.

If this does happen, though, you should not worry as you can make up for this depletion by introducing individual doses of either or each. 

Because you can add more in the form of extra supplements, we think it is always best to go from the reef salt mix that has the most beneficial elements for your coral if you will be keeping it.

If you plan to keep a fish-only aquarium, then the calcium and magnesium levels are less important than ensuring the overall alkalinity levels are adequate.

This is because fish generally need much lower calcium concentrations than harder corals do as they can form skeletons with just minimum calcium. 

Does it alter the color of your tank? 

Another consideration to keep in mind is whether or not the reef salt mix will affect your tank’s color. Whilst this may seem like a cosmetic related issue, it is actually more serious than that.

If the reef salt mix alters your tank watercolor too much, you will be less likely to see any build-up, dirt, and debris that needs cleaning.

This could harm your tank life’s health and promote the spread of disease among otherwise healthy fish and coral.

Check the information provided on each salt mix pack and all of the reviews from other customers regarding color-changing first.

We have tried very hard to choose reef salt mixes that will not alter the color of your tank water for our choices. 

Does it keep fresh when opened? 

This consideration is critical if you have a small aquarium.

If you buy a big pack of a salt mix (and they do often come in bigger packs), but you only have a small aquarium, then you may find you only need half or part of the mix.

This will mean you have leftovers. Ideally, you would want to keep the reef salt mix leftover for the next time you need to change it.

However, it is important that you only use a reef salt mix that is fresh. Therefore, you should check the shelf life of the reef salt mix after it has been opened.

Another option would be to carefully work out how much of the reef salt mix your tank will need and buy accordingly to ensure you have minimal waste. 

Frequently Asked Questions

How often should I use reef salt mix? 

You should maintain your aquarium constantly. This means changing around 20 to 25 percent of the water each month.

Every time you change this water, you will be taking away the nutrients from your reef salty mix.

Therefore these reef salt mixes need to be replenished each time you take water away. You can do this by making up the reef salt mix in advance if you wish.

As long as you are regularly keeping on top of your tank maintenance, you will easily fall into a routine and know when to use it based on your tank’s needs.

Can you mix different reef salt? 

Yes, you can mix different reef salt mixes. In fact, it is recommended if you want to switch your regular reef salt mix to a new one to do so in small increments.

This means using some of the new with some of the old gradually until you phase out the old mix.

Mixing reef salt should be safe as long as both new and old are suitable for your aquarium life, such as coral and fish. 

Does reef salt go bad? 

Unopened, reef salt can last for a very long time. This is good news for bulk buyers who favor the most cost-effective solutions for buying many months or years’ worth at a time.

The only thing to keep in mind is that sometimes moisture can get into your reef salt.

Whilst this will not make it ‘bad’ per se, it may well cause clumps and lumps to develop in the reef salt mix.

As long as it is stored in an airtight container, you can rest assured that the reef salt is likely to be fine for a long time.

That being said, we always recommend checking with the individual retailer or on the information included to be safe.

This is because all reef salts are made slightly differently, and so they may well have different shelf lives.  

Final verdict 

We bet you feel like reef salt mix experts after that! You probably didn’t even realize how many choices you had when buying reef salt mixes for your aquarium.

Our Best Reef Salt Mix article has likely already found you your new favorite.

However, if you are yet to find a reef salt mix that suits the needs of your tank or aquarium, we wholeheartedly encourage you to use the information provided for you in the Buyers’ Guide, as well as any additional information from the frequently asked questions section to help you buy the ideal reef salt mix for you. 

We are sure you can all agree now just how important it is to get the reef salt mix that is most suited to you.

It is necessary for your tank, whether it is a fish only aquarium or a mix of soft and hard corals with fish and other invertebrates.

Remember, different aquatic life forms have different needs, and you should research the needs of your particular tank inhabitants carefully before choosing a reef plant mix. 

Thank you for reading our article.

Whether you are a newbie to aquarium keeping looking for your first ever reef salt mix, or a seasoned professional hobbyist, it is always handy to have information like this to keep you in the know about the best products your tank around. 

Happy fish, happy life, as the saying goes….  

Jack Dempsey
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