How to Lower Alkalinity in Reef Tank

How to Lower Alkalinity in Reef Tank (Most Effective Ways)

You brought the fish home, got her a reef tank and all looks well. But remember maintaining her reef tank isn’t what it looks like.

There are many things you might need to be extremely careful about, one of which is its alkalinity.

Along with feeding your fish from time to time, keeping her coastal world clean is necessary. And cleaning just does not mean taking the dirt out. It also means controlling the concentration of other substances in a reef tank.

Alkalinity is the single most important element to look after if you wish to have a beautiful coral tank.

So the question arises what is that? And how am I supposed to maintain it? Hold back dear fish owners, here’s all you need to know to keep her healthy and growing.


What is Alkalinity in Reef Tank?

Alkalinity in Reef Tank

Well, alkalinity is one of the many factors you need to consider while you set a home aquarium. Fishes and other livestock in your reef tank are not very suitable for sustaining high pH levels.

The lower pH level can lead to lower alkaline levels, and a higher pH level leads to a higher alkaline level. And fishes are in danger under both of the circumstances. So what should be the pH level?

Approximately the pH level of your reef tank should be between 6.5 to 7.5, anything above or below that needs your attention. And the alkalinity of your reef tank should be 7 to 11 dKH.

This isn’t a very big issue and can be solved very easily. So without wasting any further of your time, here’s what you can do to lower alkalinity in a reef tank.


Methods to Lower Alkalinity in Reef Tank

There are different ways you can try to lower the alkalinity of your reef tank. To help you with that here are the few methods you should know.

Remember to be patient and utmost care while doing your task. Because this time you are dealing with your fish’s home and you don’t want to mess with her coral reef environments.


Change water of the Reef Tank

Change water of the Reef Tank

Yes, the first one is as simple as it sounds. Replacing the water of the reef tank can lower alkalinity and your fishes and corals can be safe in there.

You don’t need to change the whole water. Simply changing 20 to 25% of the water regularly can lower alkalinity in a reef tank.

If the alkalinity of your reef tank is way too much, consider adding some salt to it. It will slowly adjust the water parameters and your fish can do fine with it.

Your reef tank corals will likely consume some amount of water each day. So the dKH level or say alkalinity level will drop down each day.

If you are new to this, know that changing water daily solves almost 80% of the reef tank issues. It keeps your fish growing healthy and happy.

But in case you are done doing this and still, water isn’t normal, we have the next method for you. But before you try it, wait for this one for at least 4 to 5 days to see results.

Or else you are free to move on to our next method.


Organic acid to not so organic alkalinity

Organic acid to not so organic alkalinity

Adding organic acid to a reef tank can help lower down alkalinity quite quickly. It works by decreasing the pH level and eventually alkalinity.

You don’t need to go to the pet shop to get organic acid. You have it right there on your kitchen shelf.

We are talking about nothing but white vinegar. It will lower the alkalinity for sure but remember it’s temporary.

It will reduce alkalinity for now, but will likely increase in short term. You can keep changing the water of the reef tank to maintain the normal water pH.

You can also use vodka in a way to maintain alkalinity. But if it is used in even a slightly higher proportion it can be dangerous.

We say this because vodka can drop the pH level drastically. You will again have to do something to increase the alkalinity. And so experts don’t always recommend this method.

Know that the pH of the reef tank water should not drop below 0.1 or 0.2 per day. Anything more than this can have an adverse effect on your fish’s health.

So begin by adding small drops to the water tank and keep checking water parameters. If you do not notice much change you can increase the amount with time.

Both of these methods will surely lower alkalinity levels over time. We say this because our team of experts tried both of these methods.

They say it demands patience. Changes won’t be quick. You will have to wait till the corals absorb the alkalinity. Also, none of these two methods will disturb the pH level much.

You just need to be extra careful with the organic acid proportion you add to a reef tank. It not only affects the alkalinity but also the whole pH level of the reef tank.

But why does it matter the most? Why is the alkalinity of the reef tank so important?


Reasons Why the Alkalinity of Reef Tank is Very Important

Proper alkalinity is important for coral classification and the environment of a reef tank. Alkalinity helps balance the pH of the reef tank. And secondly, it provides carbonate and by-carbonate that keep corals healthy and growing.

So basically you need to be extra careful about your reef tank’s alkalinity to keep your reef tank beautiful. Also, you would be surprised to know that alkalinity and calcium go hand in hand.

When different host organisms build calcium carbonate skeletons in a reef tank, they remove calcium and carbonate from the water column. But we cannot measure carbonate or bicarbonate in reef tanks directly like alkalinity.

Different host organisms in a reef tank require calcium and alkalinity to form calcium carbonate skeletons and shells. This makes it important to not just maintain the alkaline level but also the calcium level in your reef tank.


How to Maintain Calcium and Alkaline Level in Reef Tank?

Knowing that calcium and alkalinity levels are important in a reef tank has solved half of the issue. You just need to do a few changes to your reef tank.

If your reef tank has slightly higher calcium and alkaline level sit back and relax. They will adjust naturally over time and you won’t need to add or remove anything from a reef tank.

But in case the alkalinity and calcium level is low, you need to add some amount of supplements for calcium and alkalinity. This will help balance the two and keep your reef tank looking beautiful and your corals colorful.

If the calcium is too high compared to the alkalinity of your reef tank you will need to add an alkaline supplement. It increases the alkalinity of a reef tank. Do not add calcium supplements like kalkwasser. It will only increase the calcium level.

And incase the calcium concentration is low add a calcium supplement. But if you are unable to balance that try testing magnesium in a reef tank.

Remember magnesium rating below 1200 can affect the overall concentration of water in a reef tank. So try balancing magnesium to balance either of the two concentrations.

Maintaining the alkalinity and the calcium level in reef tanks is important or it can lead to some serious problems inside your reef tank.


How to Regularly Maintain the Alkalinity in a Reef Tank?

Maintaining water parameters in your reef tank is the only way to keep your livestock healthy and beautiful. Alkalinity is one of the most important factors you need to keep a contact check on.

To maintain an alkalinity level you need to mix salt till you achieve the target alkalinity level. Do not add salt without checking alkalinity. Or you will end up making a huge change in alkaline level.

Also, make sure to regularly keep adding calcium doses as prescribed.

You can also adjust the alkalinity and pH of your reef tank by using baking soda and soda ash. It shows quick results and maintains the life of your reef tank.

Remember that you do not overdose on your reef tank with any supplement. Even a smaller change can cost you thousands.

There are various test kits available in the market that you can check for the same. A good testing kit is an essential investment you need to make for checking water parameters regularly.


Why is High Alkalinity Bad in a Reef Tank?

High alkalinity can spoil corals as well as affect the health of fishes. Higher alkalinity dissolves fish’s mucus level. This affects the overall health of the livestock inside the reef tank.

It can also affect the breathing habits of a fish, damage skin and fish can even die.

Also, higher alkalinity can affect corals’ ability to dissolve calcium. This can spoil the water quality in the reef tank making it unfavorable for use.

These changes affect the growth of livestock. And we know this is the last thing you want.

So avoiding such problems is the best way out. Changing the pH, alkalinity, and calcium level of reef tanks can affect your fish and the overall health of livestock.

The best way to keep such issues at bay is to maintain good quality water in the reef tank. So to help you with that here are few tips.


Maintaining the Good Quality of Water in Reef Tank

Maintaining the water in the reef tank doesn’t need to cost you a lot of time. It hardly takes 30 to 60 minutes a week and it’s almost more than enough. You just need to know what all you will have to do to maintain it.

Weekly Water Tests

Weekly Water Tests

Yes, you read that right. To take care of your fishes and the corals it’s important that the water has specific concentrations.

You need to check the alkalinity, calcium, magnesium, nitrate, and phosphate level of the water ina reef tank.

Proper concentration keeps corals fresh and beautiful as well as fishes healthier.


Water Changes

Water Changes

Even if the water concentration is normal, it does not mean you don’t need to change it. Changing water regularly even if not completely still works well. It keeps the environment inside the reef tank healthy for fishes as well as the corals.


Replace HOB filter Weekly

Replace HOB filter Weekly

They hang on the back filter at the back of your reef tank oxygenating the water. It is essential an essential tool and you don’t need to wait to replace it till it’s clogged. Just replace it weekly.


Recycle and replace trash properly

Livestock trash can be harmful to fishes and corals. If not cleaned regularly it can have an adverse effect on the overall livestock of your reef tank.


Control nitrogen cycle

Higher ammonia levels can be extremely dangerous to your reef tank. And so controlling the nitrogen cycle is essential. You will need an ammonia test kit for the same. You don’t need to check it regularly but quarterly or once a month will be fine.


FAQS About Alkalinity in Reef Tank

Can increasing calcium in reef tanks lower alkalinity?

If you manually add a lot of calcium supplements then it will likely lower down alkalinity. This happens because of the precipitation of the calcium carbonate in the reef tank.

But at the same time if you add too much alkaline supplement you will end up reducing calcium content. These frequent changes in reefs can affect the overall livestock badly and so it is always advisable to maintain a balance.


What do you need to balance first, alkalinity or pH?

Balancing alkalinity will buffer pH. It will prevent pH fluctuations and so it is always advisable to balance the alkalinity of the reef tank before pH. Also, it is easier to balance so you won’t likely face many issues balancing either of the two.

Remember that changes in the alkaline level after the addition of organic acid or changing water will require time. So be patient with it.


Are reef tanks difficult to maintain?

The answer is no. Reef tanks are not at all difficult to maintain if you just spend 30 to 60 minutes a week. You need to keep adding necessary supplements, maintain water parameters, clean it frequently and your reef tank will always be a beauty.



Even if the alkalinity of your reef tank is a bit too complex a concept to understand, we are sure by now what and how you can manage it.

Testing water parameters and keeping them in range will help you maintain the coral health of your reef tank.

So dear freshwater hobbyists, you do not need to worry about the sudden rise in the alkalinity level of your reef tank.

Begin with simply changing 20 to 25% of the water daily to help lower alkalinity levels. If that does not work then try adding a few drops of white vinegar.

But remember results won’t be quick. You will have to keep enough patience. We say this because corals inside the reef tank consume some alkalinity each day. It eventually causes a decrease in dKH level.

Depending on the size of your coral’s alkalinity will surely drop by 1-2 dKH per day. So don’t panic and relax. Your corals are safe because you have maintained them well. Hope you have happy, healthy, and beautiful livestock in your reef tank.


Read More:

Keep A Fish Tank Warm Without A Heater



Similar Posts