4 Tips on How To Raise the pH In an Aquarium

According to professional aquarist Douglas McComb, creating a stable environment is one of the topmost concerns when keeping your aquarium inhabitants healthy and happy. You might want to look at the tips to clean aquarium sand to maintain a clean and safe environment for your little friends!

While most captive-bred fish tolerate a wide range of pH levels, maintaining adequate amounts of alkalinity in the water acts as a buffer against dramatic pH fluctuations. Sudden changes aren’t good for your fish, and some tank residents appreciate more specific pH levels than others.

When pH levels are too low, it’s usually a sign things are off with the amounts of alkalinity in your tank. Thankfully, with appropriate regular maintenance and a few adaptations, you can raise alkalinity and get your tank back on track. If your water is testing lower than you would like, check out these expert-approved tips for when and how to raise the pH in an aquarium.

When Is Low pH a Problem in an Aquarium?

McComb explains that excessively low pH is usually a symptom of a bigger problem with very low or no alkalinity. This issue endangers the life of any tank inhabitants. Times when a slightly lower-than-average pH can be an issue include:

• Introducing new fish: If the water your new fish comes from is vastly different from your tank water, you’ll need to acclimate them to the new conditions gradually. Add small quantities of tank water to the bag of water your fish are in over a few hours before moving them to the tank.

• Keeping certain fish species: McComb explains that marine fish and some freshwater fish — including Rift Lake, Malawi, Tanganyika and Victorian cichlids — are adapted to a higher pH.

• You have a specialty reef tank: “You want to have that pH elevated for your corals and anemones,” McComb says. This promotes healthy growth.

McComb doesn’t recommend testing pH levels with paper indicator strips, as they don’t provide particularly accurate measurements. Instead, he suggests using widely available liquid drop indicator solutions to produce a more precise reading.

What Causes Low pH in an Aquarium?

Without getting too hung up on the science, some common issues resulting in low pH include:

• Soft tap water: If your tap water is low in calcium and magnesium, it’s classified as soft. These minerals reduce the amount of acid in the water, resulting in a lower pH.

• Improper maintenance: If you’re not regularly changing your tank water, it perturbs the nitrogen cycle. As pollution levels rise in your tank, so do nitrates. Excessive nitrates lower the pH and lead to problematic algae buildup.

• Tannins: Decorative driftwood leaches tannins which lower pH. However, they won’t result in a concerning reduction, and, as McComb points out, “just adding a bit of tap water with some carbonates typically offsets that.”

• Excess CO2: While CO2 in freshwater tanks is beneficial for healthy plant growth, in sensitive saltwater reef tanks, elevated CO2 levels lower pH, reduce coral growth and can result in the growth of bad bacteria. McComb sees this problem more often in new construction homes. The more draft-proof environments result in excess CO2 transferring to the tank.

McComb cautions against chasing the “perfect pH.” If your tank tenants are thriving, a stable pH is more desirable than a slightly imperfect one. However, if levels are lower than you would like, try the following tips for raising the pH in your aquarium and keeping things stable.

Do a Water Change

One of McComb’s mantras is, “the solution to pollution is dilution.” If a dirty tank is the cause of your low pH, partial water changes are one of the most effective ways of raising pH and keeping a stable and healthy environment for your aquarium dwellers.

Complete or large water changes can result in fish suffering from shock, so a maximum change of 50% is best. You can do these changes daily while you work on getting the levels up and revert to a weekly timetable once the pH is where you want.

Use a CO2 Scrubber

When your sensitive saltwater reef tank is suffering from an excess of CO2, McComb recommends investing in a CO2 scrubber. Fit this to the air intake of the tank’s protein skimmers, and it will push the surplus CO2 out and simultaneously raise the water’s pH.

Change Your Substrate and Add Shells

According to McComb, a simple and effective way to raise and stabilize the pH of a freshwater aquarium is to add or change your substrate and introduce some shells. It’s particularly useful when your tap water is soft.

Coral gravel is high in calcium carbonate, which increases the water’s alkalinity and buffers your pH higher. Select fine aragonite for maximum solubility.

Shells work the same way. Add them as a decorative element in your tank or in a bag in your canister filter.

However, if you need to raise the pH of a marine aquarium significantly, McComb explains that changing the substrate or adding shells won’t be enough. You’ll also need to buffer it further artificially.

Consider Chemical Additives

McComb isn’t a fan of using chemical additives to lower pH levels in an aquarium, but says they’re much better for raising pH. When using chemicals to reduce pH, there’s a greater risk of producing a dramatic reduction before the levels bounce right back, which is harmful to fish. It’s much easier to make gradual increases when raising pH using chemical additives.

It’s all about working out what’s causing the low alkalinity and pH levels. High chlorine levels in tap water, for example, are harmful to your fish, and they lower pH.

McComb cautions against using old-fashioned Dechlor to neutralize the chlorine. Dechlor produces a significant spike in toxic ammonia if your municipality adds chloramines. Instead, he recommends a water conditioner, such as Prime, which also detoxifies the ammonia.

Baking soda (sodium bicarbonate) is another water-softening additive that increases the alkalinity and pH of water. “So, if you’re trying to raise the alkalinity of your reef aquarium, for instance, you could use baking soda without harming it,” he says. Some aquarists use a combination of baking soda (sodium bicarbonate) and soda ash to raise pH levels of soft tap water, but it involves calculated complications to work out how much a teaspoon of baking soda will increase alkalinity. Instead, McComb recommends purchasing a ready-made tap water conditioning solution to avoid drastic swings in pH levels.

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