Can You Use Vinegar To Lower pH In The Aquarium?

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When you get an aquarium or acquire fish keeping hobby, you face a few difficulties and come across weird solutions for them. The same is the water quality and pH change that raise the questions.  Fish, and plants, and other aquatic animals require a certain pH level in order to live happy and healthy. If the pH level is too high or too low, it can make a fish sick or even kill it. A high pH level means that the water is alkaline. So, in today’s article, we are going to look at how you can use vinegar to lower pH in the aquarium.

Yes, you can use vinegar to lower pH in the aquarium temporarily. The acetic acid present in the vinegar helps to produce CO2 that, in turn, lowers water pH. But this cannot give you a permanent result so you can’t completely rely on vinegar to help you adjust pH.

Vinegar, immediately, takes the task to adjust the pH and start the ionization process in the tank but will take several hours to give a positive result. Moreover, the pH change is not subsequent and will only lower to 0.3 points.

Let’s dive in a little more in this topic to know the why, the what, the how, and the when with pH and its connection to vinegar.

Can You Use Vinegar To Lower pH In The Aquarium?

YES. This is the shortest answer to the question you have asked. You can use vinegar to lower the pH in the tank.

But keep in mind you are using an acid, however, diluted it might be, it will affect the water chemistry. Be careful there.

Don’t go for apple cider or wine vinegar, always choose diluted white vinegar that has 5% of the acid in it like Lucy’s Family Owned – Natural Distilled White Vinegar.

You see, your tank has water with higher pH due to the dissolved alkaline or basic mineral. This happens more often with tap water, so avoid using tap water in the fish tank.

The pH when steps up above 7 that’s when you need to do something to lower it. Vinegar can help you shut down the problem temporarily but it will not give you a permanent solution.

You need to keep on adding diluted white vinegar continuously till the pH is stable. Here is what happens in the tank.

When the acetic acid present in the vinegar meets the water with high pH, it combines with the oxygen of the water and ionization takes place.

This reaction results in CO2, bicarbonate, and water, and out of all this, the CO2 increment reduces the water pH making it stable.

The ionization process will start immediately whereas the production of CO2 will take several hours.

Sometimes, pH tends to get lower than it should be in your fish tank with freshwater fish. You need to increase the pH of the freshwater tank as soon as possible.

Is It Harmful To Use Vinegar Often To Lower pH In The Aquarium?

Well, you can understand why this question is most asked when it comes to using something acidic as vinegar in the tank.

Vinegar is 5-8% acetic acid and the rest of it being water, so it is only mildly acidic. This simple and diluted acid won’t do any harm to the fish.

Acetic acid helps to break down the hard water as well as the calcium and deposits them on the glass. But don’t go crazy here and use more vinegar because nothing comes good from using anything more.

You can use vinegar once in a while but not regularly. Let the water sit for a while after using vinegar and allow it to do its work.

You can use vinegar whenever the level increases and you have to adjust the pH of the tank as soon as possible.

Remember to go for the diluted white vinegar like Lucy’s Family Owned – Natural Distilled White Vinegar that has 5% acetic acid.

Never use more than the recommended amount of vinegar as a rapid decrease in water pH can affect the health of fish.

The use of more vinegar can increase the carbon dioxide level in the tank decreasing the oxygen level. You need to maintain the oxygen level in the aquarium or else your fish will suffocate, gasp, and even die.

As you know fish are very delicate, sensitive, and fragile and fluctuation of pH can even result in death.

How Much Vinegar Should You Use To Lower pH In The Aquarium?

You need to know the ideal amount of vinegar to be used to lower the pH or else you will be risking the health of your fish.

You can’t go pouring down the whole gallons of vinegar in your fish tank. So here is what you need to do: use 1 ml of vinegar per gallon of water in the tank.

For instance, you have a 20-gallons tank, thus you need to use 20 ml of vinegar in the tank and not more. This will not drop the pH subsequently but will lower it by about 0.3 to 0.4.

However, there is a drawback here; the ionization may start quickly after the administration of vinegar but will take a few hours to work and lower the pH.

How Can You Use Vinegar To Lower pH In The Aquarium?

As stated above, you can use vinegar to calculate the amount you need and pour it into your fish tank.

Go slow and don’t rush as the sudden change in water chemistry can harm the fish. You need to add it to the sump or the area with higher water flow.

This will allow the vinegar to dilute properly and spread evenly in the water. You need to make sure to increase the water movement in the tank.

But also remember not to overdo it to the point that the water current starts harming your fish. Additionally, be sure to check alkalinity and pH level more often within certain intervals, as more CO2 production can harm the fish.

Is It Okay To Use Vinegar To Lower pH In The Hydroponics?

The case for hydroponics is not different than the fish tank. The same thing happens here as well, so you may know the answer already.

Let’s simplify it so that it doesn’t seem confusing for people with hydroponics. The answer to the question you asked is Yes.

Yes, it is okay to use vinegar to lower pH in the hydroponics but it is a temporary solution again. You can’t fully get rid of the high level of pH with simple vinegar.

It is better to switch to more natural options that are listed below in this same article. read it completely to understand what you need to do and what not to do.

Factors That Cause The Increment Of pH In The Aquarium

pH doesn’t increase itself without some factors hampering their way. Few factors that increase the pH in the aquarium:

Type Of Substrate Used

Sand substrates have a high amount of silica in them that eventually leads to an increment of pH. Also, some other substrates that have been chemically modified have certain chemicals that fluctuate the pH of the tank.

Trace Mineral Content

If you are using tap water for your fish tank and your water pH keeps on hitting the high basicity mark, it is because of the mineral content.

That’s why it is not safe to use tap water in the fish tank. The traces of mineral is high and alkalinity comes naturally to it.

Failure Of Filtration System

When your aquarium filtration system and its media fail to do its regular task, the water pH level tends to increase or decrease.

The cloudy and foamy water in the aquarium as well as the unclear and dirty water is the clear sign of filtration system failure.

No outlet of harmful chemicals remaining in the tank or change in the CO2 level will make the pH higher towards the basic range.

Aquarium filter needs to work properly to maintain ideal pH for the fish all the time. Make sure to check it time and often and clean the mechanical media too.

Change In Chemical Composition Of Water

The production of CO2 due to the high ionization of water changes the chemical composition as well as pH. Also, sometimes the pollutants and fish waste keep on increasing producing more ammonia.

This can also lead to chemical war within the tank and resulting in pH fluctuation.  Neither more nor less production of CO2 will help you here, you may not be able to stabilize the pH all the time but you can handle this.

Overfeeding your fish will lead to more fish waste, more leftovers, and many more issues that will definitely change the composition of the aquarium water.

Use Of Medications

Sometimes you use certain medicines for your fish to remain healthy or cure certain diseases they were showing symptoms to.

Hence, the medication can also affect the water pH and makes it worse if it remains untreated, uneaten, or unchecked.

Decorations In The Tank

Some decorations have certain alkaline properties like limestone and chemical composition with bicarbonate.

These little things can make a difference, small but rarely huge, in the water pH making it go higher than the ideal given mark.

Why Is It Necessary To Lower pH In The Aquarium?

If you have been researching well about various species of fish and what a pH change can do, you would have known the consequences.

Some fish make adjust well in the basic water but most of them don’t. You need to make sure the pH is within the ideal range to keep your fish healthy.

Also, the rapid change and continuous fluctuation in the water pH can be harmful to any fish. So, it is very necessary to adjust the water pH in the aquarium.

Water pH also has a direct impact on the increment or decrease of toxicity in the tank. The change in pH causes the water to go toxic and will harm the fish as well as plants present in the tank.

High pH indicates the presence of a high level of alkali and base that might harm the fish as well as the aquatic plants present in the tank.

Your whole tank ecosystem is in jeopardy when any of the ideal parameters don’t meet like pH, temperature, water quality, or general hardness.

Can You Use Vinegar As Cleaning Agent In The Aquarium?

Yes, you can use vinegar as a cleaning agent for your aquarium but can leave an after smell. It is quite easy to clean with vinegar as it is to use vinegar to lower pH in the aquarium.

Take 1 cup of vinegar per gallon of water i.e., 1:1 ratio of a cup of vinegar and gallon of aquarium water. Do not rush here and pour down the diluted solution into the water.

Simple take a scrubbier or a rag and scrub gently in the water where you need it to be cleaned. Also, remember to neutralize the water using buffers like bicarbonate.

Vinegar is acetic acid, even mild and diluted, that can harm the fish by fluctuating the pH of the tank.

How Often Should You Test pH Of The Aquarium?

Water pH tends to change throughout the day and is quite unstable. But it needs to be checked once in a while to make sure it is within the ideal range.

You need to check all the water parameters, not only pH, once a month. Remember to test the pH in the same hour every time because the result varies throughout the day.

Same time and same hour help to understand the consistency or change in the pH level. Likewise, make sure you check pH and other water parameters when your fish gets sick before using any medications.

What Are The Other Ways To Lower pH In The Aquarium?

As we have already established why it is necessary to adjust the water pH and vinegar can’t be a permanent solution, you need something that can help you in long run.

Here are the few solutions that can be somewhat better than vinegar and the natural ones always a step ahead in every game most of the time.

Water Change

Water change can help you adjust the pH without using any other chemical or natural components. The water needs to be in the ideal condition so that the fish can live.

But the unusual spike of ammonia, failure of filtration system, a spike of nitrate, or other issues can bring a change in water dynamic.

Ammonia production and poisoning in the aquarium is one of the main causes of the pH rise following right behind by the mineral content in tap water.

So, it is necessary to change 20 to 30% of the aquarium water once or twice a week. It is better to go for a water change within the 5 days intervals.

This will keep the pH as well as all the toxic components in check giving the fish the ideal environment to live in. Also, remember too much aquarium water change is harmful to your fish so, keep it subtle and ideal.


The fish tank gets dirty very fast and you need to clean and maintain it to get the ideal pH range. Various aquarium filtration methods are there that can help you clean out the debris as well as grime present in the tank.

One of the main causes of the increment of pH in the tank is ammonia. So, you need a filter with various filter media along with biological media.

Biological media houses beneficial bacteria that perform the aquarium nitrogen cycle. This nitrogen cycle helps to converts the toxic ammonia into an essential compound.

You also need to clear the filter mechanical media once in a while for its smooth functioning. The large debris and pollutant can clog the filter and the unclean filter will, no doubt, underperform or fail eventually.

This will all lead to water quality change that’s why you need to keep your aquarium filter in check all the time.

Substrate Change

The sand substrate can sometimes contain silica in it that can increase the basicity of the water. So, go for a substrate that does not contain chemicals with a high concentration of alkalis and bases.

Also, you have to remove grime using a siphon kit like Toopify Aquarium Fish Tank Clean Tools from the gravel as well as vacuum the substrate once in a while.


Proper aeration with the help of an Aquarium air pump can help to maintain the pH of the tank. Surface agitation and oxygen supply are the main work take care of by aeration.

The increased level of CO2 once the aeration is cut can help to lower the pH without any further issues. But you have to monitor and check the pH and oxygen level closely.

The low oxygen level can cause shortness of breath and suffocation in the fish that can eventually lead to death.

Reverse Osmosis

This is quite a popular technique to lower the pH of larger fish tanks. You need a filter that is based on RO technology and it is quite applicable for larger tanks whereas most of the other solutions are for small tanks.

This filter might cause a dent in your wallet but it is worth it. It uses a semi-permeable membrane to filter the water and is a long-term solution for pH stability.

What it does is, it filters out the traces of minerals that are present in water responsible for spiking the pH.

LiquaGen-5-stage Reverse osmosis filter with 75-gallons tank capacity is highly recommended if you have a large tank.

Peat Moss

Peat moss is applicable in two ways: one directly into the tank and the other soaking into the water that will later be introduced to the tank.

The second method is more reliable than the first one as it is easier and faster to introduce like that. Peat moss releases tannic acid that lowers the pH of the tank.

Peat moss is also introduced to the filter in the form of pellets and flakes and will release tannins while filtration takes place.

But it is also responsible for discoloring the aquarium water while releasing the tannins and you have to be okay with it.

Remember to purchase peat moss that is free from chemicals like Fluval Aquatic Peat Granules, 6 Marimo Moss Ball Variety Pack, etc.


Driftwood and peat moss have the same mechanism to cope with the higher pH to get it lower. It, too, releases tannic acid that helps to lower the pH.

You need to go for driftwood that is free from dye, chemicals, etc., and is specifically made for fish tanks.

You will need 1 driftwood for a small 10-gallons tank whereas you can get 2 for a little larger tank. This can release color along with the tannic acid so it is better to soak in water for a few weeks.

Or you can boil the wood for 5 minutes to sterilize and remove toxic components along with the color before introducing it to the aquarium.

If you plan on buying driftwood, go for WDEFUN Natural Coral Driftwood that comes in two pieces and will go well with a 20-gallons tank.

Almond Leaves

Almond leaves are the leaves of Indian almond trees that have the property of lowering the pH level with the help of tannic acid.

These leaves are dried to use in the aquarium so that they can release tannic acid as soon as they are dipped in aquarium water.

They will gradually lower the pH with the help of acid so it is best to sink them to the bottom rather than the surface of the tank.

These leaves can last up to 6 months or a year but will be necessary to change after this to avoid any side effects.

They also serve the decorative purpose and the release of tannic acid with yellowish color even adds attraction to it.

This process not only helps to lower the pH but also give the shy fish enough hiding space. SunGrow Large Catappa Indian Almond Leaves is one of the best in the market that can be used for multi-purpose and recommended.

Frequently Asked Questions

The answers to a few FAQs are given below:

How much vinegar do you use to clean a fish tank?

It is quite a simple thing to remember while cleaning a fish tank with vinegar. The ratio of water to vinegar needs to be 1:1. Go for half-gallon for the small aquarium whereas 1 gallon for a larger tank.

Remember not to use anything else like soap while cleaning the tank with vinegar.

Can you use baking soda to clean a fish tank?

Baking soda works wonder as a cleaning agent as it solves the cleaning problem in two ways. The first one is when you soak your dirty tank in the baking soda solution.

Here is what it will do, the baking soda will react with the dirt and greasy substances. It will break them down and attach to the tank surface.

Another way is when baking soda acts abrasive to remove algae that are kind of stubborn along with the grime. These are always attached to the glass and easier to clean with baking soda.

Baking soda is such a softer that it will clean and will not even leave a scratch in the glass.


In conclusion, vinegar can be a temporary solution for your permanent problem in the fish tank. So, it is better to go for other natural remedies rather than this. Vinegar can help you get a small window till you manage another solution but don’t depend on it. It is chemical after all and the slightest mistake can affect your fish. Also, the after smell is quite terrible so it is better to leave this one unless it is an emergency.

Recommended Articles:

  1. How to Increase pH Level in a Freshwater Tank?
  2. How to Lower pH Level In Saltwater Aquarium?
  3. Maintain Aquarium Water Hardness – Freshwater Aquarium Guide
  4. Freshwater Aquarium Equipment Checklist : Aquarium Supplies You Need