Fish tank pH level
The term pH stands for “power of hydrogen,” and is the measure of a scale used to describe how acidic something is. Although all fish have an optimum water pH that they thrive in, most can adjust to live in slightly suboptimal pH conditions. What’s more important is maintaining a relatively stable pH.
All fishkeepers should know how to check aquarium pH levels, what helps to maintain stable pH levels and when and how to lower the pH in an aquarium.
What’s the correct pH for an aquarium?
There’s no exact correct pH level for an aquarium. The majority of fish do well in water with a pH of somewhere between 6.5 and 7.5, though certain species may prefer slightly higher or lower levels. If you have a mixed group of fish in your tank, aim for a pH around the 7.0 mark. Fish can die if pH levels in their water fluctuate by more than 0.3 in a day, so it’s best to concentrate on maintaining a stable pH, even if it’s slightly outside of the optimal range, rather than trying to hit an exact 7.0.
How to check aquarium pH
You can buy kits to test for aquarium pH, such as the API Aquarium pH Test Kit. Simply follow the instructions to find out if your aquarium pH is within a safe range. Alternatively, you can use a more overarching test kit, such as the Tetra EasyStrips 6-in-1 Aquarium Test Strips, which test for five other water parameters in addition to pH, including hardness, nitrates and nitrites. If you’re worried about the pH levels in your aquarium, it’s best to check them weekly so you can spot issues before they get serious. Otherwise, every two to four weeks will suffice.
Should you adjust your fish tank’s pH levels?
Now comes the tricky question, should you adjust your aquarium water’s pH levels if they’re slightly too high or too low? It might seem like “yes” is the obvious answer, but it isn’t as simple as that. The pH of tap water is never going to be extremely high or low, otherwise it would burn you like a strong acid or lye. What’s more important to most fish than the exact pH level is that the pH in their water is maintained at stable levels. So, it’s better that the water in their tank stays consistently at 6.0 than fluctuates between 7.0 and 7.4 in a day. You can test whether the pH in your tap water remains stable by letting a bucket of it sit out for 24 hours, testing the pH and then testing it again after 48 hours. If the pH remains stable, it should be good to use in your aquarium. You can also test for carbonate hardness (kH) using a kH test kit. Water with a higher kH corresponds with a more stable aquarium pH.
How to lower pH in an aquarium
If you must lower the pH in your aquarium, it’s important to do so carefully. Adjusting the pH by more than 0.3 over 24 hours will stress your fish and could kill them.
Reverse osmosis
The best way to lower the pH of your aquarium water is to use a reverse osmosis system. This removes the substances in your water that raise pH levels. The downside to reverse osmosis systems is that they’re relatively pricey and must be installed beneath a sink to filter water before it comes out of the tap, so it’s best for serious fishkeepers only, or anyone who’d also like to filter their drinking water anyway.
Add natural tannins
Certain products that you can add to your fish tank naturally release compounds called tannins into the water that slightly lower pH. This is a good way of slowly and marginally lowering pH in a way that won’t stress your fish. Natural driftwood is an excellent source of tannins, and it also looks good in aquariums and gives your fish extra spots to hide out. You can also add peat granules or pellets to your filter, though the harvesting of moss isn’t great for the environment, so it shouldn’t be your first choice.
pH lowering products
You can buy specific pH lowering products for aquariums. It might seem like using these would be the best way to lower your aquarium pH, but although they’re easy to use, they aren’t ideal. In general, pH lowering products have a tendency to cause fluctuations in pH where levels lower before springing back up again, which is worse for fish than simply living in slightly high pH water. These products are best used before adding fish to a new aquarium, so you can monitor for fluctuations.
Lauren Corona is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money.
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