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When it comes to our reef tanks and marine aquariums, there’s nothing more important than the right balance of pH, calcium, and other elements for the safety and health of our critters and fish. And reef salt, in some cases.

Creating that balance comes through having the right testing kits, the right equipment – such as filters and RO systems – but it also comes from using the right substrate and reef salt.

Everything in your miniature eco-system requires certain qualities to avoid raising pH levels, destroying beneficial bacteria growth, growing out bad bacteria, et cetera. And the best reef salt is a huge part of that.

Best Reef Salt Quick-Find Table

Image Product

  • Specially designed for use in reef and marine aquariums
  • Very fast acting
  • Low cost per gallon
  • Specially designed for use in reef and marine aquariums
  • Very fast acting
  • Low cost per gallon

  • Designed with hard corals and anemones in mind
  • Instant dissolve and easy to use
  • Adds calcium and extra nutrients that help brighten corals
  • Designed with hard corals and anemones in mind
  • Instant dissolve and easy to use
  • Adds calcium and extra nutrients that help brighten corals

  • Great for people who aren’t 100% sure on their needs
  • Really excellent blend of compounds
  • Easy to use and learn from
  • Great for people who aren’t 100% sure on their needs
  • Really excellent blend of compounds
  • Easy to use and learn from

  • Affordable, even in bulk rates
  • Feeding for all aquatic life
  • Appropriate for all coral and fish ages
  • Affordable, even in bulk rates
  • Feeding for all aquatic life
  • Appropriate for all coral and fish ages

Why the Right Reef Salt is So Important


One of the biggest issues many newbie aquarists hurtle is understanding and using the right reef salt. It’s just salt, right? How hard could it be?

But reef tanks and marine aquariums are a whole different style of fishkeeping from freshwater tanks with super easy fish like goldfish and guppies.

In fact, a reef tank is a bit like the actual barrier reefs out there in that they are very delicate eco-systems.

Remove the ability to naturally grow under a tropical sun with natural lighting, natural sand, and a larger ecosystem to feed many of the other aspects of growth.

And your marine and reef tanks may actually be more delicate than the wild glories of a reef.

Because of this we’re all looking for the best reef salt to use.

But as some other folks on the internet have mentioned, the right blend is more the issue, rather than the “right” brand.

Some brands make incredible products available to us, but that isn’t a guarantee that the reef salt they offer is right for our systems.

Each aquarium is a unique eco-system unlike any other aquarium, the ocean, or bay in the world. The exact combination of animals and fish is different.

Author note: The exact lighting settings, position in a room, food sources, et cetera are all a little different from each other and impact your aquarium’s healthy balances.

Some products definitely outshine others – and one of the things I do always recommend in any search is looking for well-known, well-trusted brands.

But overall, the best reef salt for your aquarium is going to be based on your specific needs.

The salt you use in your aquarium effects the water stability of the environment.

Top tip: If you just choose the top pick from someone’s best marine salt for reef tank list without doing any testing of your own, you could find that you have thrown the balance totally out of whack.

And that’s a huge problem that you’ll have to spend the next several weeks – or even months – fixing.

To avoid that, though, let’s look at some specific things on how to choose the best marine salts for your aquarium.

What to Look For in Reef Salt

Just to reiterate this critical point: every aquarium is a little different from the next and has different needs. 

SPS corals, for example, need different trace elements and water parameters than LPS tanks. It’s just a fact. Just like humans have different medical proclivities, animals do, too.

So, let’s look at how you can figure out which salt mix is best for your reef tank.

Research Your Aquarium’s Needs


This is the first and most important step to choosing your aquarium salt.

Unfortunately, since I’m not there with you, I don’t know all of your needs.

And that means you’ve got some research ahead.

You need to look up the information for each of the critters you keep so that you can understand what needs they have.

Top tip: I’d recommend doing some in-depth searching and forum discussions at sites like Fish Forums and Nano Reef.

Here you can post a question about your specific species and learn from long-time hobbyists and pros who really know what they’re talking about.

Understand the Differences Between Synthetic and Mined Reef Salt Mixes

Exotic sea fishes in a aquarium

Mined sea salt generally comes from evaporated natural seawater ocean deposits.

This is likely to be very close to many natural environments but may or may not be suitable for your specific needs.

Others are pulled directly from the ocean.

Synthetic salts are man-made mixes and tend to be very popular in Europe. Though natural is usually best, a lot of times these synthetic salts are actually better for coral reef tanks because of the higher purity.

Choose the Options Closest to Your Ideal Parameters

Salt mixes are made up of a blend of elements, both major and minor, and these are how you can ultimately determine the best salt mix for your reef aquarium.


Calcium is the foundation of reefs. Corals build their skeletons from this critical mineral through a process called biomineralization.

Important Note: Without calcium, hard corals and stony corals cannot build and maintain healthy bodies. Calcium elements in your salt can help corals grow healthy and strong.


Alkalinity is not an ingredient of salt, but salt can affect it. pH levels in a fish tank, no matter what type, need to be within precise parameters all the time.

The type of tank you keep has different parameters than another, so be sure of your precise needs.

You want a salt that will not negatively impact the alkalinity and pH balances of your aquarium.

Top tip: The right pH helps your corals build their skeletons through the calcium and stable alkalinity helps prevent the nasty pH fluctuations that cause issues in this area.



Magnesium is sort of your catalyst in the reef. It helps to ensure calcium and alkalinity levels are in balance.

Our aquariums also need this element for healthy growth and life otherwise, as well, as it is a key element for biological development.

Reviews of the Best Reef Salts

Because reef salt has such a huge impact on the health and life of your aquarium, we did loads of research and study to make sure we’re only recommending the best reef salt mix and options to help you find the right choice.

Each reef salt option we review is made up of a variety of different qualities to suit different needs, but they all hold true to these parameters:

  • High-quality care and processing
  • Solid reputation among long-time fishkeepers and newbies alike
  • Good balances of elements
  • High ratings and lots of data to dig through from users

#1. Instant Ocean

instant ocean

From a trusted brand with a solid knowledge of what aquariums need, the Instant Ocean Sea Salt for Marine Aquariums without Nitrate and Phosphate is an excellent choice for any reef tank aquarist.

It’s extremely popular with hobbyists and used widely in loads of aquariums, including public aquariums and scientific research facilities.

  • Calcium: 400 ppm
  • Alkalinity: 11 dKH
  • Magnesium: 1320 ppm
  • Size: 200 gallons
  • Best for: Fish-only reef tanks, soft corals

What We LoveD

We love that this sea salt blend is a fast dissolving option for adding to aquarium water. That means your water is ready sooner and easier than with some of the slower options out there.

We also love that they specifically work with this blend to prevent it from upping the pH, adding nitrates or adding phosphates to your carefully cared for reef tank.

It’s complete with the trace and major minerals you need for a healthy tank and is incredibly easy to use in your tank.

We also love that this is an affordable option for folks on a tighter budget. The price per gallon undercuts a lot of the competition but still delivers all the benefits of a high-quality sea salt reef tank blend.

Finally, you’ll love the consistent results like we do. It’s great for reef tanks, marine tanks, and specifically fish only reef tanks.

What We Didn’t Love

The one drawback we saw is that this isn’t so great for marine and reef tanks that have hard corals. In fact, many aquarists have said it’s best for fish only tanks, specifically.

If you’re in that line of fishkeeping, though, this is your best bet.

Our Verdict On Instant Ocean Sea Salt

Overall, this is a great option – the best overall, in fact – for reef tanks.

It’s best for fish-only and soft corals – definitely no hard corals – and does a fast-dissolving, efficient job at helping to increase salinity while not increasing negative levels like nitrates and phosphates.

Use as directed, ask a few questions of other aquarists if you’re not sure on exact measurements, and enjoy the benefits.

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#2. Instant Ocean Reef Crystals

instant ocean reef crystals

A close second on reef salt is another winner from Instant Ocean. The Reef Crystals Reef Salt is a highly popular option for reef tanks, especially those with hard corals.

It’s been specifically formulated for reef tanks that have a higher nutrient demand – like hard corals do – with extra calcium and other trace elements that help build healthy, happy coral.

  • Calcium: 490 ppm
  • Alkalinity: 14 dKH
  • Magnesium: 1440 ppm
  • Size: 200 gallons
  • Best for: Reef tanks, hard corals

What We LoveD

Instant Ocean is a fantastic brand with a great reputation for high-quality ingredients, processing, and service in the fishkeeping industry.

And they haven’t strayed from their standards with this fantastic reef salt that’s designed specifically with hard corals in mind.

The reef salt has extra calcium and trace minerals specifically setup for hard corals that need extras on these elements, and we love that. Hard corals can be a real challenge, so getting the extra built-in help is fantastic.

The reef crystals also help to detoxify any metals in the water – those nasty heavy metals found in tap water. You filter needs to do the trick, but the reef salt helps to give an extra kick in the pants to that elements.

And like the other Instant Ocean Reef Salts, Reef Crystals dissolve quickly and easily.

We also love how affordable this salt for saltwater aquariums is. Quick, easy – can’t beat it.

According to everything we could discover and experience, it doesn’t separate after long periods of storage, so you can buy this ahead of time – like when there’s a great sale! – and use whenever you need to boost the salinity levels.

What We DIDn’t Love

We’ve not really found any issues, but there have been some reports by users of brown residue, while others have said a white residue in the tank.

In the unlikely case that it becomes cloudy, check out our guide on dealing with cloudy fish tanks.

Our Verdict On Instant Ocean Reef Crystals Reef Salt

If you’ve got hard corals you’re trying to help flourish, then Instant Ocean Reef Crystals is your best bet.

We’ve seen some reviews looking for instant ocean vs reef crystals on the care, and the main difference is that the first is for soft corals and fish only tanks, while Reef Crystals are for hard corals.

They’re equally great and equally recommended for your best reef tank life.

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#3. Red Sea Coral Pro Salt

Red Sea coral pro

While obviously we all need to do our research, if you’re someone who’s struggling to get it just right, this is a great one to start with.

The Red Sea Pharm ARE11230 Coral Pro Marine Salt for Aquariums is one of the easiest to use blends for marine and reef tanks because of the “ideal” ratio between compounds that they’ve calculated out.

It’s not 100% for every tank, but it’s a really great place for beginners to start and learn and grow through the use of.

  • Calcium: 465 ppm
  • Alkalinity: 12 dKH
  • Magnesium: 1390 ppm
  • Size: 175 gallons
  • Best for: Beginner marine and reef tanks

What We Loved

The main reason this wins the day for new hobbyists is because of the compound ratios. Figuring out the exact balance can be tricky – especially if math and science aren’t your thing – and this basically does it for you.

It works for multiple types of saltwater aquariums, so it’s the best jumping off point you can find until you’ve got that deeper knowledge.

Next, we love the fact that this helps to accelerate healthy coral growth.

In other words, it does what it’s supposed to without you having to figure out every exact detail. Just keep the testing going on your calcium, magnesium, and other levels, to ensure you’re giving those little polyps everything they need.

We also love that it’s a really great option for heavily stocked reef aquariums. That means all those fish and corals will still thrive thanks to the balance of extra nutrients.

Finally, this is a super easy to use salt thanks to the balance provided and the fact that it’s a fast-dissolving option.

What We Didn’t Love

We’ve seen a couple of potential drawbacks, though they’re not significant.

First, we’ve seen some reports express that the boxes have arrived damaged – though no damage to the salt.

It’s possible it was a shipping/packaging error, as they seem to be in a similar period of time, but you may find this happens to yours when you order.

Also, because this is so great for beginning aquarists, some have had issues with really low stocked tanks or fish-only tanks.

The extra nutrients of the profile aren’t necessary for low numbers, so if you’re running a less stocked tank, you may wish to choose a different option instead.

Finally, it’s not the cheapest choice. We kind of feel like it should be cheaper, since it’s not as precise a formula as some of the others – i.e. more generic in use, though equally useful – and shouldn’t reflect the prices of more premium selections.

Our Verdict On Red Sea Coral Pro Marine Salt for Aquariums

Despite the higher price, we really do recommend this for beginner aquarists. You’ll find a much more natural balance to start out from that you can build on and grow with as you learn.

Be sure to use for heavily stocked reef tanks and those with corals, et cetera, not fish only tanks, though. And keep up the testing to make sure the nutrients aren’t too abundant for your aquatic life to fully manage.

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#4. Brightwell aquatics neo marine salt

Brightwell Aquatics reef salt

This is your best salt mix for reef tank choice if you’re keeping a fish only tank, especially with who do better with elevated levels of calcium, strontium and magnesium. The Kent Marine Saltwater Aquarium Salt Mix is easy to use and fast dissolving.

While some reef salt mixes are designed with certain species of fish in mind, the Brightwell Reef Salt blend is actually made as a “broad feeder” style mix.

This means it works for corals, fish, and other reef tank needs – no specialization needed.

This, of course, means it’s for a broader spectrum reef tank, though, and not a specialty tank.

  • Calcium: 400 ppm
  • Alkalinity: 7.9 dKH
  • Magnesium: 1050 Mg
  • Size: 16 to 300 gallons
  • Best for: Broad needs reef tanks

What We Loved

First off, we love that this works for your more general reef tanks, covering the needs for most tanks without extra supplementation needed.

We love that this is actually a really great choice for nano reef tanks, thanks to those high supplements.

We love how fast dissolving this salt mix is. That makes it easy for anyone to use.

What We Didn’t Love

Because it is such a general blend, we wouldn’t actually recommend this one for beginners, which is a bummer.

Beginners should aim for a more specialized blend to meet their precise needs with more room for error.

Our Verdict On Kent Marine Saltwater Aquarium Salt Mix

While it’s not the end-all of reef salt mixes, the Brightwell Aquatics Reef Salt Mix is pretty darn good. It’s great for nano reef tanks and broad needs (general) reef tanks with a lot of profiled needs.

We just wouldn’t recommend it to beginners.

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FAQs on Reef Salt


Is there a difference between salt for soft and hard coral?

There are some minor differences in the reef salt blends that work better for soft versus hard corals. However, this is a case by case situation that you need to look into for specific parameters for your species.

How much reef salt should you use per gallon?

Generally speaking, most reef salt producers recommend about 1/2 cup of salt per gallon of aquarium water.

However, this can vary from company to company, so please carefully read instructions and use their recommendations, if provided.

Is there a difference between reef Salt vs marine salt?

When you look at a marine salt versus reef salt comparison, you’ll see that the primary differences are the amounts of given elements that make up the salt blends offered.

The labels and adverts should clarify the levels of each for the products for help with your decision making process.

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