Learning how to lower the pH in your aquarium is an essential skill when it comes to maintaining a healthy fish tank.
But it can seem a bit intimidating at first.
You see, this is not knowledge that is available during the purchase process. You can run out and buy a tank with some fish in it, and at no point in the process will you be taught what to do.
Unfortunately, this leads beginners to get ahead of themselves and set up a tank they are not prepared to maintain. All of this makes the process frustrating for them and dangerous for their fish.
That’s where this guide comes in. She will teach you how to lower the pH in her aquarium using the most effective methods.
By the time you finish reading it, you will be fully prepared to make adjustments to your tank when necessary.
Reason for lowering the pH
So when would you need to lower the pH in your fish tank anyway? Is it one of those things where high pH is bad and low pH is good?
These are all questions we get from newer aquarists, so it’s important that we address them before we teach you how to do it.
pH levels are simply a unit for measuring how acidic or basic certain water is. The scale runs from 0 to 14, with the higher the number being less acidic, and a pH of 7 means the water is neutral.
It is also logarithmic. That means a pH of 5 is 10 times more acidic than a pH of 6, and a pH of 4 is 100 times more acidic than 6.
Author’s Note: There is a lot of useful scientific information. resources you can visit if you want to learn all the essentials. But for the purposes of this guide, we’ll keep this part pretty high.
This is very important because each aquatic species has an ideal pH range for its water. For example, some fish do best with a pH of 7.5 to 8.5 and others require a range of 5.8 to 7.
Some can tolerate a wider range than others, but everyone has a limit. This stems from each species’ adaptation to water in its natural habitat, which is why we include recommended pH levels in all of our care guides.
If the pH level begins to rise above this required range, it is very important that you lower it. Water that is too basic will lead to serious health complications, such as damage to the gills of the fish.
If the pH rises too high and is not corrected, it is very likely to have fatal consequences. Not good.
Methods to lower the pH of the aquarium
Now that we’ve scared you off, it’s time we taught you how to lower the pH of your aquarium. We like to do this naturally when possible, but we’ve listed a variety of effective methods to give you plenty of options.
But remember this first:
It is incredibly important to gradually lower the pH of the tank. As you probably know, sudden changes in water parameters can cause serious problems for all kinds of aquatic life.
So even if your tank has too high a pH level, slow and steady wins the race. It’s better to lower it gradually and steadily over the course of 48 hours than to do it all at once.
1. Add peat
One of the best ways to naturally lower the pH in a fish tank is by adding peat moss. In fact, this is our favorite method overall (which is why we put it first).
>Many aquarists are a bit skeptical when they hear about this technique. It can’t be that easy, right?
But it is.
Peat is acidic and rich in tannins. By simply adding it to your aquarium, it will begin to gradually lower the pH level (depending on how much you add).
All you need to do is pick up some from your local garden store or nursery and put it in your filter. Storing it in the filter allows the peat to impact the water more effectively and stay out of the way (it will float all over the place if you just drop it in your tank).
You will probably notice that your water will turn a little yellow after you add it. If aesthetics are important to you, simply soak the peat elsewhere to reduce this effect (soak it in water that has similar parameters as your tank).
Author’s Note: The only tricky part about using peat moss is that there is no formula for determining how much to add. The most effective approach is to add a little, wait, test the water, and then continue adding more if its pH is still too high.
2. Include some driftwood
Including some driftwood is another way to lower the pH in your aquarium naturally. While we like peat a little better in terms of its effectiveness, driftwood still does a great job!
The good thing about relying on driftwood as a way to keep the pH level in check is that it works as a hiding place for various fish! You’ll find that in many of our care guides we recommend including driftwood for this reason.
You obviously need to make sure there is room in your fish tank before you add it, of course. If things are already a bit tight, we recommend trying another method from this list.
You should only consider adding aquarium-safe driftwood, as other types are only made for terrariums or the dry part of paludarium (aka not meant to be underwater). These varieties are treated with chemicals that can be toxic to aquatic life.
While there are ways to take driftwood that isn’t designed for fish tank use and make it safe, it’s much more of a headache than it’s worth. Not only will you spend a lot of unnecessary time doing this, but there is never a 100% guarantee that it will be completely safe.
Just save yourself the hassle and get aquarium-safe driftwood.
3. Perform partial water changes
Partial water changes are another great way to keep pH levels in check. This is something you have to do on a consistent basis for most of the creatures you keep in an aquarium, but this will give you another reason to make time for it!
A partial water change is helpful because it improves the overall quality and cleanliness of the water in your tank. When you exchange some of the water in your tank, you are removing some of the organic waste that naturally accumulates in the tank (leading to high ammonia levels).
Obviously, you can’t change all the water at once without having another home for life in your fish tank, so this is where a partial change comes in handy. Most of the time, the goal is to achieve a 20 to 30 percent change.
This is more of a maintenance tactic than a turnaround tactic, but that doesn’t make it any less powerful. Making sure your pH is in the proper range means it’s much less likely to rise and much easier to lower if necessary.
4. Add catappa leaves
This is another effective and natural way to lower the pH in any freshwater aquarium. Catappa leaves (also called Indian almond leaves) can have a huge impact on your tank water and the life within it.
>Starting with the obvious benefit first, they can lower pH levels. These leaves will release a large amount of tannins into the water, which will affect the acidity over time.
But that’s not the only thing they do.
Adding catappa leaves to your water can also protect your tank from fungal and bacterial infections! While this may sound too good to be true, it is scientifically proven.
Many of the more experienced aquarists we know keep these leaves on hand and use them to treat their tank directly or spray them as a maintenance and prevention strategy.
With these, you don’t need to worry about getting them into your filter like you would with peat moss. Just break them up as best you can and add them directly to your tank.
Don’t go overboard with these. Add them gradually over time and test the parameters of the water as you go.
5. Use reverse osmosis
This is a trick to lowering the pH in fish tanks that many aquarists don’t know much about. That’s because it’s a bit more complicated than the other methods and requires you to have specific equipment.
However, you can’t argue with the results!
The water created through reverse osmosis is as pure as possible. It is devoid of chemicals, water hardness, and completely neutral when it comes to pH.
This process also removes almost all of the debris that accumulates in the water over time.
That means you will have much more consistency when it comes to water conditions, which will make it MUCH easier to lower the pH in your tank. While there is always an element of uncertainty with the natural methods on this list, using reverse osmosis puts you in complete control.
Obviously, the downside is the cost. These machines are not cheap and will require some maintenance throughout their lifespan. It’s a bit more complex than just adding peat moss or catappa leaves!
If you’re looking to go all out and have a larger tank (these don’t fit nano aquariums), reverse osmosis is a great option. You will be able to lower the pH in your aquarium with ease and maintain highly stable conditions.
Make sure you get accurate readings
One of the most common mistakes new aquarists make is with the quality of their test kits. They buy an inaccurate kit that regularly gives false or incorrect readings.
This tricks them into thinking they need to lower the pH in their aquarium when in fact they don’t. In other words, this causes them to unknowingly injure animals in their habitat.
Do yourself a favor and get reliable equipment so you can make well-informed decisions. This is the only one we recommend:
now you’re ready
Now that you have learned how to lower the pH of your aquarium, there is nothing to fear!
When you pull back the curtain, it becomes clear that many parts of fish farming are more intimidating without the proper knowledge. It’s more about being consistent and caring about the welfare of your fish!
While there are other methods to lower the pH in a freshwater tank, we are not including them for a reason. The options we listed above are effective, powerful, and reliable.
Many of the other less common tactics are not.
We are always open to discussing new methods and tricks to lower pH, of course (this is how we improve and discover new tricks). But for the purposes of this guide, we wanted to stick with the classics.
If you have other methods you’ve been trying or have had success with, we’d love for you to share them. We are always eager to learn and would definitely consider adding something interesting to this guide in the future.