How Much Aquarium Salt Per Gallon (A simple guide)

Salting aquariums have some benefits for your fish, and it has been in use for a long time among experienced aquarists. For starters, aquarium salt performs medication purposes, among other benefits.

Now, the problem isn’t with what benefits or what to use them for, but getting the right measurement for your aquarium. Just as it’s easy to oversalt food, you can overdose your aquarium with salt and kill everything living in there if you don’t have the right measurement guide.

How much aquarium salt per gallon, you may wonder? Read through this article to get your answer!

What is Aquarium Salt Used For?

How Much Aquarium Salt Per Gallon

Generally, people use aquarium salt to improve the overall well-being of fish in the tank. Aquarists often add it in small doses in the tank as a form of medication for fish.

One of the reasons aquarists do this is because sometimes, during water changes, the aquarium tends to lose some electrolytes, which the salt can help supplement. As a newbie, you should know that aquarium salt is very useful for fishkeeping. 

It helps you maintain the ideal salinity level in the tank and keep your fish healthy. So, what are their benefits?

1. Stress reduction

You can use aquarium salt to reduce osmotic stress. When a fish is sick, it can experience some stress resulting in osmotic shock. As a result, it removes electrolytes from their gills. 

It also affects their breathing process, inhibiting them from taking in oxygen and releasing carbon dioxide. However, aquarium salt contains electrolytes that can help reduce stress and improve gills’ function.

2. It can serve as an anti-pathogen

In aquariums, pathogens such as fungi and bacteria are bound to appear and cause harm to your fish. However, adding aquarium salt will increase the salinity level in the tank and dehydrate fungi and bacteria.

3. Create brackish water

You can also use aquarium salt to create brackish water. This is for fish living in aquatic conditions with more salinity than freshwater. You can make your tank more habitable for those fish using aquarium salt. 

4. Treat ailments

A lack of electrolytes in aquarium tanks can cause health problems for your fish. It affects their gill functions, and breathing, and causes other severe health problems. 

Aquarium salt can help treat injuries, improve slime coating, fight parasites, reduce nitrates, etc. You only need to know how to use it right.

Types of Aquarium Salt

With the enticing benefits of aquarium salt, you may be tempted to grab any salt and pour it into your fish tank. But that’s not how it works. If you use salt that’s inappropriate for your tank, it may become a problem for your fish.

The most suitable aquarium salts for your fish tank are:

1. Freshwater aquarium salt

You can say the one aquarium salt fit for your fish tank is freshwater aquarium salt. It helps reduce stress, enhance medication, and increase hardness in a freshwater tank.

Some examples are:

2. Non-iodised rock salt

Non-iodized rock salt is somewhat similar to table salt based on the presence of sodium chloride. However, table salt has the iodine element, which the non-iodized rock salt doesn’t have. They also contain less potassium, and using rock salt is more effective than using non-iodized salt.

3. Marine aquarium salt

Marine aquarium salt contains minerals and elements that help keep fish healthy. For example, they help balance aquariums’ pH, alkaline, calcium, and strontium levels.

It helps keep water at a positive level good for your fish. Here are some examples:

Can Table Salt Replace Aquarium Salt?

Table salt and aquarium salt are totally different. You may think it’s okay to use table salt in aquariums, but you really shouldn’t. Why?

Because they contain iodine. You can only replace aquarium salt with table salt if it doesn’t have iodine. Of course, fish need iodine for their health, but they already get enough of that from their food. 

Overdosing them on iodine can be harmful, so if you know the table salt you intend to use in the tank contains it, you’d better not use it. 

Additionally, table salt shouldn’t have additives like anti-caking compounds. Therefore, ensure you check the labeling for all that so you don’t end up harming your fish. 

How Much Aquarium Salt Per Gallon?

What’s the answer to the question: how much aquarium per gallon? There is no specific or general answer to that. Instead, it depends on the intended usage. 

1. For disease prevention or regular usage

The best way to treat disease is through prevention, and you can use aquarium salt for that. If that is the major thing you need it for, you should add 1 tablespoon of aquarium salt into every 5-gallon of water.

So, the bigger the tank, the more tablespoons you add to it. This rule applies to freshwater generally without irritating the fish living there. 

2. For brackish water

If you have brackish fish and want to make the aquarium habitable for them, you need to add the appropriate amount of salt to form the ideal salinity level. For brackish water, the salinity level is between 1.005 to 1.012. 

To get exactly that, you should add 1 to 2 tablespoons of aquarium salt into the tank.

3. For disease treatment

Aquarium salt helps in treating diseases in fish tanks. When you fail in preventing diseases, that’s what happens. Treating fish with aquarium salt is in three levels, and you need to start from the lowest to the highest.

4. First dosage

You need to start with a low dosage of 1 tablespoon for every 3 gallons of water. This is ideal for freshwater tanks because this salt level is bearable for them. 

If your fish don’t look any better within a week, you can increase the salt treatment.

5. Second dosage

When you don’t notice any change, it is time to increase the salt concentration in the tank. Therefore, add 1 tablespoon of aquarium salt to every 2 gallons of water. 

This helps deal with serious diseases such as ick. However, some diseases can be stubborn, or the salt can be ineffective on some, so you need to intensify the salt concentration if you don’t see any change in a week.

6. Third dosage

You’ll use 1 tablespoon of aquarium salt for every 1 gallon of water for the third dosage. This will help tackle intense disease conditions like bacteria, fungi, and parasites.

While this is effective, it can be too much salt concentration for freshwater fish and affect them. Fish like catfish and others without scales can hardly handle or survive this.

Therefore, when doing salt treatment, you need to monitor your fish for any behavior changes. Once you notice your fish has gotten better, you need to remove the salt from the tank through gradual water changes.

The water change should be at 30% per week because a sudden change may affect the fish. Even after salt treatment, some diseases may return.

When they do, gradually increase the salt concentration as you’ve done before.

How To Mix Aquarium Salt

If you’ve never mixed aquarium salt before, you must know how to get it right. It is a very simple process; therefore, you don’t have to worry.

Before you get started, you need the following:

Steps to follow:

  1. Fill up the clean container with water. When adding the water to the container, use a filter or dechlorinating solution to prevent water quality issues.
  1. Turn on the heater and pump to circulate water and increase it to 78°F.
  1. Start adding the salt based on the recommended dosage.
  1. Let the water pump mix the water and salt until there are no salt granules left in the tank. 
  1. Check after 30 minutes for salinity level. Add more salt if it’s too low and more water if it’s too high.
  1. Leave the mixture for hours or days to let it settle and keep checking, as explained in step 5.
  1. If you want to create an aquascape, add sand and rocks to the water before introducing the fish.
  1. Mix more saltwater in the container and add it to the aquarium to raise the salinity level.
  1. Leave the filter in for several days before removing it to extract debris from the water.

How To Measure Salinity Level in An Aquarium

You need to check the salinity of your aquarium at all times so your fish can stay healthy. Generally, an aquarium’s salinity level should be:

  • 1.000 for freshwater
  • Between 1.005 and 1.012 for brackish water
  • 1.025 for ocean water

The lower the salinity in the tank, the lesser salt mix you would need to use during water changes. With that said, you need the following to measure the salinity level in an aquarium:

The most used is the refractometer, but the digital device is more accurate. 


How much aquarium salt per gallon for your fish aquarium depends on why you need it. Generally, you can use aquarium salt to prevent and heal diseases in the tank. 

And with the right measurement, you can get your fish to be healthy again. However, salt can affect live aquatic plants in the aquarium, so use caution or create the mix in a different container.

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