Skip to main content
  1. Home
  2. Other animals

Is the pH in your aquarium normal? Here’s how to tell

Rebekkah Adams
By

All aquarists know that taking care of fish is tougher than it looks. Your bird, hamster, and dog breathe the same air that you do, but tank dwellers have specific needs for their environment that you have to monitor. In addition to oxygen and nutrients, you have to closely watch pH levels. If you think back to high-school chemistry, you’ll remember that pH measures how acidic or alkaline something is (like lemon versus baking soda). The ideal pH will vary depending on your fish and whether you’re looking at a saltwater or freshwater ecosystem.

Hand holding a pH testing kit next to an aquarium
M-Production/Shutterstock

How to test pH in an aquarium?

To find your pH level, you’ll need a good testing kit and you’ll want to test frequently. Before trying this out, though, check your water source. It’s helpful to know the pH of your water before it goes into your tank when you’re figuring out how to adjust it. For most tanks, you should be testing biweekly to maintain the correct levels. Keep a record of every reading and check water under the same conditions each time, meaning the same time of day and approximately the same number of hours after feeding.

Recommended Videos

You have a few different methods for analyzing your water, ranging from testing strips (least accurate) to digital testers (most accurate). With strip kits, you first draw some of the tank water into a tube. Next, you add a drop of the testing solution and wait for it to change color. Compare the water color to the color-coded strip, which will tell you the pH value of your tank. You may need more than one kit if you have different tanks with different pH requirements.

Fish swims in an aquarium
Delbert Pagayona/Unsplash.com

What is a good pH level?

The optimum level will depend on which fish you have in your tank and what the environment is like. Generally, the pH of a freshwater tank will run a little lower than a saltwater one. For freshwater, you’re looking at anything between 6.5 and 7.5. Adjust depending on the fish you have and be mindful about putting together only species that like similar acidity levels. Some freshwater fish fall out of this range, too, like certain types of tetras, which means you’ll have to find others who can coexist in that specific range if you mix species.

Related

For a saltwater aquarium, you want something more in the 7.6–8.4 range, but reef tanks need to stay on the higher end. If you’re growing coral, you need to pay particular attention to stabilize the pH between 8.0 and 8.4, so make sure the fish you have will thrive with the coral.

What causes high pH in an aquarium?

You may test your water when you set up your tank and find it perfect, but slowly pH starts to creep up or down. A few things can cause this, and unfortunately, some very regular processes can contribute to it. If you notice your pH level going up, it could mean you have too many plants or stones. Because plants “breathe” CO2, they can change the water quality toward alkalinity. Your rocks, too, might slowly dissolve, releasing calcium into the water. These are both common problems and easily fixed by removing some of the offending decorations, then testing again for any change. 

The symptoms of low pH in a fish tank are a little different. This usually results from fish waste that is not properly filtered out. Sometimes fixing it will be as easy as replacing your filter pieces to bring them back up to maximum ability.

How to fix your pH level?

There are some quick ways to raise or drop the level, but determining the culprit behind your pH issues will be just as important, or it will keep getting out of whack. Commercially available treatments will help easily change things up. If your pH is too low, adding a few more rocks or shells will make a difference and will keep working, rather than acting as a one-time fix. Likewise, removing these and adding driftwood or peat moss brings down your pH level.

Unfortunately, significant pH drops, or very acidic water, can kill your fish, so you need to be vigilant about testing and adjusting. Living in water not right for your fish will cause extreme stress and even burns on his skin if it’s too far outside his comfort zone. Remember, staying relatively consistent within the range is important, too. With proper testing, you’ll keep him happy in his perfect environment.

Editors' Recommendations

Rebekkah Adams
Rebekkah Adams
Contributor
Rebekkah’s been a writer and editor for more than 10 years, both in print and digital. In addition to writing about pets…
Is buying a baby turtle illegal? Here is how to bring home this reptile legally and ethically
Follow a few rules to ensure you bring home a turtle the right way
A very small turtle sits in the palm of someone's hand outside

Turtles have exploded in popularity, becoming one of the most coveted pets. They can be great additions to the family — while Testudines require some specialized care you don't need to take them on daily walks. But along with the rise in turtle ownership, some other problems have emerged, like disease outbreaks and illegal trading. Because of these issues (namely salmonella), the sale of small turtles, set as those with shells of less than 4 inches, is banned in America.
So does that mean you can't own a turtle unless you meet someone in a trench coat for the exchange? There's a right way to go about this and we'll tell you how.

What are the problems with owning a turtle?
Before you jump into any reptile ownership, you should carefully research their needs and behaviors. Because they're an entirely different class of animals from us, they don't necessarily act the way you might think. In addition to all the usual worries, like preventing animals from being kept in inhumane conditions, there are three main problems that can occur with irresponsible turtle ownership.
Salmonella
We noted at the top that turtles have been linked to salmonella outbreaks. You need to get your animal from a reputable pet store, preferably in your neighborhood and not online (where shady deals can be harder to spot). On top of that, the CDC recommends that no one keep turtles in a house with any humans under 5 or over 65 or who have a compromised immune system.
Illegal trading
As mentioned, more and more people are bringing home these beasties and as a result, some unethical importers have turned to wild-caught creatures. In many places, this is illegal, but that doesn't stop people from capturing and then selling them to families. These actions have contributed to dwindling populations and low birth rates among some turtle species around the globe.
Abandonment
When you bring home any animal, you commit to them for life. In the case of a turtle, that could be decades. These pets are occasionally included in wills because they live so long! Because of that, they are often taken to a creek and let loose, sometimes with devastating results.

Read more
How to tell if your guinea pig loves you – some ways may surprise you
These are the signs your guinea pig loves you as much as you love him
A happy guinea pig hangs out in the grass

We know how much we love our pets. The question is if they love us, too. It can be tricky to tell how animals feel since they can't tell us about their moods. But that doesn't mean we can't ever figure out what's in the minds of our furry friends.

Guinea pigs in particular make a lot of interesting noises and show postures that help us decipher their thoughts and feelings. By paying close attention to your little guy and learning a bit about how he thinks, you can get a pretty good sense of his inner goings-on. And you won't have to watch very long to confirm that your guinea pig loves you.

Read more
Is your fish tank for bettas too small? Here’s are the do’s and don’ts of betta care
Care tips to keep your new betta fish happy in the right size tank
A betta swims with plants in its tank

While the betta craze may have died down a little, you still see many of these beautiful blue fish in homes and in stores. It's true that they make great pets, even for a novice aquarist, since they don't require an overly extensive tank setup and often prefer to be alone. But just because they work well for a newbie doesn't mean you can dive in without any research. We're here with what you need to know about betta fish care and fish tanks for bettas. Here are the do's and don'ts for bettas.

What do I need to know about taking care of my betta fish?
Do research fish breeders
It all starts with the betta egg, and even the mom and dad. Just like with a puppy, you want to ensure your fishy has had a good life from hatching. There are tons of ethical breeders out there, but you can find some shady ones, too. In general, you want to avoid stores that have them crammed into tiny containers and cycled in and out every day. Do your research about local pet fish stores in your area or check out some of the more reputable ones online.

Read more