Home » Aquarium Guides » Muriatic Acid To Lower pH In Aquarium (The Correct Way)

Muriatic Acid To Lower pH In Aquarium (The Correct Way)

Welcome back to the life of fish blog to find answers to your aquarium-related problems. In this article, I am going to explain how Muriatic Acid (Hydrochloric Acid) helps To Lower pH In Aquarium. As you might know, muriatic Acid is well-known for its ability to lower the pH in Pools. It was very popular in the 1970s and 1980s. However, it has largely been replaced by more modern and effective methods. Still, some aquarists use it, so it’s worth discussing.

There are different opinions on using Muriatic Acid (Hydrochloric Acid) to lower the pH in aquariums. But the truth is, you can, in fact, use it for your fish tank. You just need to be careful and know what you’re doing.

Muriatic Acid To Lower pH In Aquarium

What Happens To Fish If pH Is Too High?

If the pH in your aquarium is high, it can cause stress to your fish. This can lead to disease and death. A high pH can also make it difficult for your fish to breathe. When the alkalinity level goes beyond the recommended level, it becomes toxic to fish. This is because the water becomes too basic, and the gills of the fish can’t function properly. The fish’s gills, eyes, and skin are all irritated by high pH levels. This can cause problems with their respiratory system, vision, and even their ability to swim. Higher pH can also damage the metabolic system of fish, resulting in sluggishness and a decrease in appetite. In short, a high pH level is dangerous for fish and can even be lethal.

What Is The Fastest Way To Lower The pH In A Tank?

There are a few ways to lower the pH in your fish tank. But the fastest way is to use Muriatic Acid or Hydrochloric Acid. Muriatic Acid is a strong acid, and it will quickly lower the pH in your aquarium. However, you must exercise caution when using it. But, Word of Caution, just because Hydrochloric Acid lowers the pH of water fast doesn’t mean that you should lower the pH fast. Sudden changes in pH can be just as harmful to fish as a high pH.

You should always test the water before and after adding Muriatic Acid. And you should only add a small amount at a time until you get the desired pH level.

Is Hydrochloric Acid Toxic To Fish?

Hydrochloric Acid is not toxic to fish when used properly. But, as with anything, there is always a risk of overdoing it. If you add too much Muriatic Acid to your fish tank, it can lower the pH too much. This can be just as harmful to fish as a high pH. According to some studies, when the pH of water is lowered down to pH 3.0 to 3.5 by acids like sulphuric, hydrochloric, and nitric acids, it can cause a 50% mortality rate of fish within 96 hours. So, as you see, high concentrations of hydrochloric Acid are toxic to fish. This is why it’s so important to only add a small amount at a time and test the water after each addition.

Can I Use Muriatic Acid In My Fish Tank?

Yes, you can use Muriatic Acid in your fish tank to lower the pH. But, as we’ve already discussed, you need to be careful. Always test the aquarium water before and after adding Muriatic Acid. And only add a small amount at a time until you get the desired pH level.

Muriatic Acid To Lower pH In Aquarium

Muriatic Acid ( Hydrochloric Acid) To Lower pH In Aquarium

I like to explain this using some chemical terms. Muriatic Acid changes the water’s chemical structure and produces new ions (hydronium ions and chloride ions).

HCl + H2O = H3O+ + Cl.

This reaction will lower the pH of the water by dissolving the alkaline minerals in the water. Unfortunately, the chemical produced (chlorine and chloramine) by this reaction is toxic to fish. So, to make the water safe for your aquarium fish, you need to take a few more steps.

How To Use Muriatic Acid To Lower pH

Some aquarists suggest adding hydrochloric Acid directly into the tank water, but I don’t recommend it. This is very dangerous to your fish. What I do is, add the Acid to a water container and then slowly pour it into my aquarium.

You’ll need to add enough Muriatic Acid to lower the alkalinity by 2-3 dKH. (You can learn about dkH here.) To find out how much acids need to add, I need to check the alkalinity of my tank water before and after adding the Acid. I do this by using an aquarium test kit. I use API Freshwater Master Test Kit for this. Once I know the alkalinity of your water, I calculate how much Muriatic Acid need to add. For example, if the alkalinity of my water is 10 dKH and I want to lower it to 7 dKH, I need to add 3 dKH of Muriatic Acid.

If you have no idea about these calculations, you can add a small amount of Muriatic Acid to the container of water and then slowly pour it into your aquarium. After each addition, you should test the alkalinity of the water until you get the desired level.

Important: You MUST keep the acid-dissolved water aside for about 24 hours before pouring it into your aquarium. Before pouring it, you should use a dechlorinator or an aquarium-grade water softener to remove the chlorine from the water.

How Long Does Muriatic Acid Take To Lower pH?

It depends on how much Hydrochloric Acid you add to the water. If you add a small amount, it will take longer for the Acid to lower the pH. And if you add a large amount, it will lower the pH faster. However, lowering the pH fast is not always a good thing because it can be harmful to fish. This is why I recommend only adding a small amount of Acid at a time and testing the water after each addition.

Muriatic Acid To Lower pH In Aquarium

Safety Precautions When Using Muriatic Acid

When using any kind of chemical, there is always a risk of accidents. This is why you need to take some safety precautions when using Muriatic Acid. When using Muriatic Acid, you should always:

Wear gloves and protective eyewear

Since Hydrochloric Acid is a strong acid, it can cause skin irritation. Therefore, it is critical to wear gloves when working with Acid. To avoid getting Acid in your eyes, you should also wear protective eyewear. Never touch the Acid with your bare skin or eyes.

Work in a well-ventilated area

Muriatic Acid releases fumes that can be harmful if inhaled. So, it’s important to work in a well-ventilated area when using the Acid. If you don’t have access to a well-ventilated area, you should wear a respirator to avoid inhaling the fumes.

Add the Acid to water, not water to acid.

Never add water to Muriatic Acid. Always add the Acid to the water. If you do it the other way around, the Acid will splash and can cause skin irritation or even blindness.

Never add more than 1ml of Acid per 250 liters of water.

As mentioned before, adding too much Acid can be harmful to your fish. So, it’s important only to add a small amount at a time.

Never add muriatic Acid straight into the tank.

A single drop may not harm your fish, but sometimes, the chemical reaction may cause the death of your fish. Therefore, it’s better to be safe than sorry.

Stop using the Acid if you see any adverse effects.

If you see any susceptible effects on your fish after adding Muriatic Acid, stop using the Acid immediately and do a water change. Some of the adverse effects you may see are:

  • Fish gasping for air at the surface of the water
  • Fish swimming erratically
  • Fish lethargic and listless
  • White patches on fish body
  • Fish death

If you see any of these adverse effects, stop using the Acid and do a water change immediately.

Keep the aquarium well-ventilated.

Muriatic Acid gives off fumes that can be harmful to your fish. So, it’s important to keep the aquarium well-ventilated when using the Acid.

Test the pH of the water before and after adding the Acid

You should always test the pH of the water before and after adding Muriatic Acid. This will help you to make sure that you’re not adding too much Acid to the water.

Keep the Muriatic Acid away from children and pets.

Muriatic Acid is a dangerous chemical that should be kept away from children and pets. If ingested, Acid can cause serious health problems. So, make sure to store the Acid in a safe place where children and pets cannot reach it.

Conclusion

As I mentioned in this article muriatic Acid is an excellent way to reduce the pH of your aquarium. However, you must take precautions when using it. Test the water before and after adding muriatic Acid, and only use a small amount at a time. You can safely use Muriatic Acid in your aquarium if you follow these guidelines.

Muriatic Acid To Lower pH In Aquarium

Is Muriatic Acid Reef Safe?

Yes. Many reef hobbyists use Muriatic Acid to lower the pH and alkalinity in their reef aquariums. Many hobbyists state that their reef aquariums are doing well with the Acid. But coral reefs are very sensitive to high pH. High pH slowly dissolves the coral reef. Therefore always follow the guidelines and add as less acid as possible. 

What Are The Risks Of Using Muriatic Acid?

The main risk of using Hydrochloric Acid is that it’s a strong acid. So, if you’re not careful, it can cause skin irritations or even blindness. That’s why it’s important to always wear gloves and protective eyewear when using the Acid. You should also add the Acid to water, not vice versa. And, only add a small amount of Acid to the water at a time. If you follow these guidelines, you’ll be able to use Hydrochloric Acid safely.

Credit to : starwind aquariums

Read Next: What Is Mulm In Aquariums? (Benefits And Drawbacks)

Sharing is caring!

About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.