How to Raise PH in a Saltwater Aquarium

How to Raise PH in a Saltwater Aquarium

One of the key things you need to monitor to ensure the vitality and health of your aquarium is its pH level. Extremely high or extremely low pH could lead to the ill health or death of your fish. 

Whether you are an amateur or an experienced aquarium hobbyist, you’ve most probably heard or read about the significance of monitoring the pH level in saltwater aquariums. The significance is to help you maintain a slightly high pH level in your saltwater aquarium.

This is because most saltwater fish and creatures are adapted to a high pH level of about 8.2. Therefore, maintaining your aquarium at roughly the same high pH level creates the perfect environment for them to thrive.

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In this post, I will share with you some of the methods you can use to raise the pH level in your saltwater aquarium. But before we take a look at the methods, let me explain to you what aquarium pH is and the things that can reduce aquarium pH.

Let’s begin.

What is aquarium pH?

Aquarium pH is basically the measure of how alkaline or acidic the water in your aquarium/ tank is. It is normally measured on a scale of 0 to 14, with 7.0 signifying a neutral pH level. Any level above neutral is described as alkaline while the levels below 7.0 are said to be acidic. 

The pH of saltwater aquariums is generally maintained at between 7.6 and 8.4. The fish, invertebrates, and coral species found in your tank will, however, determine your aquarium’s ideal pH. This means that you have to conduct some research on the inhabitants of your fish tank to find out the ideal pH level to maintain.

Causes of low pH in saltwater aquariums

Any pH value of less than 7.6 is considered to be a problem in saltwater aquariums. Below are some of the causes of low aquarium pH


Ammonia can significantly reduce the pH value of your tank. Even though it is classified as a weak alkali, the various biological processes involved in its production release hydrogen ions which can reduce aquarium pH.

You should note that ammonia is toxic to most living things including marine creatures. Therefore, if you discover your tank’s pH to be low, you should also test for increased ammonia levels. Any detectable ammonia in your tank will be deadly to saltwater creatures and you should do everything to eliminate it immediately.

Excess carbon dioxide 

Increased levels of carbon dioxide is another plausible cause of reduced pH in your aquarium. This normally occurs when the aquarium water does not move a lot as the stagnation or near-stagnation usually results in poor aeration.   

Your saltwater tank needs currents and when your power-heads and pumps breakdown and the water is not really moving around in the tank, poor aeration occurs. You can luckily correct this with the help of circulation pumps or wave-makers, which ensure that your water is well aerated. This will balance out the carbon dioxide content and raise the pH.

Other causes of low pH in saltwater aquariums include:

Incompletely cycled aquarium

If your tank is not properly cycled, its water chemistry will not mature enough to have the right pH and to sustain life.

Carbon dioxide/ calcium carbonate reactor

Adding carbon dioxide to aquariums lowers pH. 

Now that you know what aquarium pH and that you also know the things that can reduce your aquarium pH, it is time for me to share with the methods that can increase your saltwater aquarium pH.

Methods you can use to raise the pH of your saltwater aquarium

Sodium bicarbonate/ baking soda 

This is one of the most commonly used methods for raising the pH of saltwater aquariums. It should, however, be used only when excessive carbon dioxide is not the reason behind your tank’s low pH. 

To use this method, begin by preparing for a partial water change similar to the way you would during regular tank maintenance. Replace a single water gallon for every twenty in your tank. Next, measure a teaspoon of sodium bicarbonate for every replacement gallon and then mix it in. 

Note that the teaspoon measurements should be level and not the biggest mound that you can actually scoop with your spoon. Over the duration of about an hour, pour in the treated water little by little. This will increase the level of your aquarium pH.

Chemical buffers and supplements

Certain chemical buffers and supplements can be used in raising pH. Most are inexpensive and quite easy to use. Some might, however, raise pH a bit too quickly.

A lot of aquatic creatures respond poorly to abrupt changes in pH, even if the shift is to a favorable pH. In addition, some products need pre-dilution or addition to a sump and not the main tank thus making them complicated to use. Nonetheless, most supplements that raise the pH come with the added bonus of boosting the water’s calcium levels, which consequently improves the health of organisms living in your tank.

Special aquarium decorations

You could passively increase and buffer your tank’s pH by dropping aquarium decorations that leach bicarbonates and calcium into the water. The best aquarium decorations for this job are coral sand and calcium-rich rocks such as tufa. They gradually but steadily release calcium. 

One advantage of this method is that it is cheap. Nonetheless, because it is slow, it might not keep up with various biological processes that reduce pH levels. So do not use this method alone if you need to increase pH level fast.

Proper aquarium maintenance practices

Following proper aquarium maintenance practices such as regularly changing the water and not overstocking your aquarium will prevent the build-up of ammonia and keep your tank’s pH level high.

Calcium reactors

Calcium reactors are made to improve calcium levels and not to increase aquarium pH. However, when installed, they buffer the aquarium water and make it difficult for pH levels to drop. 

This method’s only downside is that calcium reactors are expensive and challenging to set up. But if your aquarium includes calcium-hungry creatures, investing in a calcium reactor is definitely a wise thing to do.


The secret to keeping the fish living in your saltwater aquarium healthy and happy is maintaining a healthy environment for them in the tank. One of the most important ways to do this is to constantly monitor the aquarium pH and increase it if need be because most saltwater creatures thrive in a high-pH environment.

As you have seen, high pH levels of about 8.2 are ideal for most saltwater aquariums. Conducting regular water tests will alert you of any sudden pH changes. In case of any noticeable drop in pH, you need to take action to correct the situation before it has a negative impact on your fish.


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