How to make saltwater for aquarium fish at home?

how to make salt water for aquarium header

Not everyone is lucky enough to live near the sea.

So many of us need to learn how to make saltwater for our aquarium fish at home.

Although it may seem simple, creating your own salt water requires more than just mixing salt and water together. Also, there is no hard and fast rule for the right amount of salt per gallon of aquarium water, as it depends on the salt mix you are using.

I created this step-by-step guide to walk you through the process, so you can easily make your aquarium water safe for your pets.

How to make salt water for your aquarium fish at home?

To make salt water, you will first need a few pieces of equipment. Here is what you will need:

  • Submersible thermometer
  • sea ​​salt mix
  • Submersible pump or powerhead for water circulation
  • Hydrometer or refractometer to measure salinity
  • Water reservoir
  • Aquarium heater

The first ingredient you will need to make seawater at home is sea salt.

There are several brands of sea salts available in the market, but of all the ones I have tried, Instant Ocean is the most cost effective. It’s relatively inexpensive, blends clearly, and gives you the same results as some of the more expensive brands.

instant ocean product

by C-Reefer

Red sea salt is also a viable alternative, especially for reef aquariums. It contains a perfect blend of minerals that enhance coral growth and coloration.

By the way, I would like to add that most fish shops also offer pre-mixed salt water, but I wouldn’t recommend using that.

Its quality is questionable at best and you don’t know how long it has been sitting on the store shelf gathering dust. I have also heard reports from other aquarists who have experienced algae blooms after using pre-mixed saltwater purchased from their local fish store.

In terms of container size, you can use a simple plastic bucket to mix seawater if your aquarium is small. However, if not, using a plastic canister would be a better idea.

This way, you can make your saltwater in one batch rather than mixing several.

Make sure the container you are going to use is clean.

If it has been used for other purposes and you suspect there are traces of contaminants remaining, you should buy a new one instead of trying to clean it.

In my experience with this, prevention is better than cure.

The few dollars you save buying a plastic bucket could end up costing you a fortune by destroying your entire tank.

Either way, after making sure you have all the necessary equipment, you can move on to the actual process.

Here’s how to prepare saltwater for your home aquarium:

1. Fill a container with dechlorinated water

fill the container with water

by ajjw0828

You should avoid using plain tap water for your saltwater tank. This is because it can seriously harm or even be the end of your pet fish if it has not been properly conditioned beforehand.

Water treatment facilities disinfect tap water with chlorine and chloramine which are toxic to fish. In addition to their toxicity, these substances also destroy the beneficial bacteria responsible for eliminating waste from our aquariums.

Ideally, you’d have distilled water on hand for your mix, but that’s rarely the case in any household. So, to make tap water safe for your saltwater aquarium, you must first dechlorinate it so you can get rid of chlorine and chloramine.

This can be done naturally or with a water conditioner. You can just wait long enough for the chlorine to release, but most tap water contains the more stable ChlorAMine.

Boiling is another method of natural dechlorination, but it’s basically not practical for keeping fish, so just use some kind of aquarium water conditioner. Something like Seachem Prime should do the trick.

Author’s note: Since marine life is very sensitive to contaminants in the water, by definition most aquarists avoid using tap water for their tanks without purifying it. People usually use what is called an RO/DI system for purification. An RO/DI system is a set of filters that pass your tap water through different purification processes such as reverse osmosis (RO) and deionization (DI).

That being said, there are people with successful aquariums that don’t use an RO/DI system for their tap water.

Anyway, when measuring the amount of salt water for your aquarium, you must take into account that there must be a free space at the top to allow for splashing and turbulence.

2. Place a water pump and a water heater at the bottom of the container

mixing tank

by DaddyFish

The speed at which the salt will dissolve will depend on the temperature of the water.

Salt dissolves more slowly in cold weather, so using a heater will reduce the time it takes to mix the salt water.

The ideal temperature for this would be between 75 and 78°F (between 23.8 and 25.5°C). Higher temperatures will only increase the chance of precipitation forming.

In addition to temperature, circulation also affects the rate at which salts dissolve.

When the salt particles are in motion, they are suspended in water, causing them to dissolve at an accelerated rate.

By combining the two methods, you will speed up the whole process considerably and ensure that there will be no more salt residues afterwards.

3. Add sea salt mixture to water and stir

add sea salt

Designed by katyhoser

Before adding the salt mixture to the water, carefully read the instructions on the box.

Although most brands recommend adding half a cup of sea salt per gallon of water, there are a few exceptions to this rule.

It’s also a good idea to scoop a little less salt than recommended on the label.

If the salinity is below the desired range, you can simply adjust it by adding more salt.

After reading the instructions, proceed by gradually adding the sea salt to the water while stirring at the same time.

If you put all the salt in the container at once, it will settle to the bottom and form a residue.

Important: You should never add sea salt directly to an aquarium. Always mix salt water separately and carefully monitor its salinity levels. Pouring sea salt directly into a tank containing live fish, invertebrates or sea plants can cause serious harm to them.

4. Use a refractometer or hydrometer to measure the specific gravity of water

hydrometer and salinity tester

by Taxus812

After thoroughly mixing the saline solution, you should measure whether it is within the desired salinity range.

You can do this in two ways.

The first is to use a hydrometer and test the “specific gravity” of water.

Clarify: Specific gravity is a measure of the density of a given substance relative to the density of a reference material. Substances with a specific gravity greater than 1 have a higher density than their reference material.

In our case, we use water as a reference material and compare its density to that of salt.

Seawater typically has a specific gravity of around 1.025 to 1.026, so ideally yours should mimic that.

The second and most reliable way to check if your water is in the correct salinity range is to use a refractometer.

Refractometers measure the refraction of light to determine salinity levels.

When light enters water, it bends or refracts at a certain angle. The degree of this angle depends on the concentration of salt or other particles in the water.

By measuring this angle, refractometers also help us know the density of our solution.

sea ​​water refractometer

by bpaston

Most saltwater refractometers typically have both PPT (parts per thousand) and specific gravity scales.

If you measure the amount of salt in your saltwater solution in PPT, you should aim for 35 PPT.

If after mixing the salt water, its salinity is found to be less than 35 PPT, you should adjust by adding more sea salt.

To calculate the exact amount, you need to add approximately 0.01 (4.44 grams) of sea salt per gallon (3.78 liters) of water for each PPT below the target value.

Let’s say your refractometer returns a reading of 33 PPT.

This means you will need to add 0.02 pounds of sea salt to the solution for every gallon of water to raise the salinity to 35 PPT.

This would equal 2.4 pounds of sea salt per 120 gallons of water.

However, if the salinity is 34 PPT, you will need to add half that amount or 1.2 pounds for the same volume of water. You can use this salinity calculator if you want to experiment with values.

This calculator is also very useful if you are trying to bring your water to brackish salinity. Either way, when you’re done with the measurements, let the salt water sit for 24 hours.

This should be enough for oxygen and carbon dioxide levels to reach a steady state. Once the water has stabilized, go back to check its salinity again.

If not within the specified range, adjust accordingly until you reach the desired salinity level.

Don’t worry, you rarely have to adjust after 24 hours.

my last words

marine fish aquarium

by William

Setting up a marine aquarium is a process that requires a certain set of skills.

By learning how to make saltwater for your aquarium fish, you learn a valuable skill that will help you along your journey in the aquarium.

So, which fish did you choose for your new aquarium? Here is a list of fish ideas for complete beginners in this part of the hobby, if you haven’t decided on anything yet.

Share your plans for your new tank with other readers in the comments section.

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