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What Exactly Is pH?
Solving the mystery of our fish’s health can sometimes be confusing, but one factor that is often overlooked can easily stress our aquatic pets unnecessarily. That factor is known as pH, or “potential of hydrogen,” which is the unseen quality of the water in terms of acidity or alkalinity.
The pH scale is measured from 1 to 14, with 1 being the most acidic, 14 the most basic (alkaline), and 7 being neutral. Most freshwater fish thrive best in water that is maintained between 6.5 and 7.5 pH. Saltwater fish can do better in a slightly more alkaline environment, ranging usually between 7.8 and 8.5.
Before determining exactly what pH to target in your water, it is smart to do some quick research on your fish specifically and their requirements. Keep in mind that it is best to keep a mix of fish who require approximately the same levels, so that one or the other is not stressed at the expense of another.
What Are The Symptoms Of High pH In A Fish Tank?
Unusual energy in the fish
You might notice your fish swimming quickly or in a sporadic and excited manner. On the other hand, it can also induce lethargy, causing the fish to not move much at all.
Difficulty breathing
The fish will often be found hanging out near the top or the bottom of the water. At the surface, they may appear to be gasping for air. At the bottom, they may be simply trying to absorb as much oxygen as possible at the deepest point.
Intentional injury
Scratching themselves on the aquarium decorations or the rocks is another reaction that fish typically exhibit under high pH levels. At very high levels, you may even see them attempting to jump from the tank.
Loss of appetite
Fish may lose their appetite in addition to their lethargy under these stressful conditions.
Physical changes
Some bodily changes may be noticed such as the development of white spots (ich), widespread fins and slimy gills.
Increase in algae
A sudden expansion of algae across the walls and ornaments may send up a red flag that pH levels are too high.
Deteriorating plant health
The health of plants can also be affected by high pH levels. If you notice plant health starting to deteriorate, it’s time to do some testing.
Cloudy water
Water that appears cloudy may be the result of calcium not be dissolved properly, a symptom of high pH levels.
What Causes pH To Rise In An Aquarium?
While pH regularly oscillates in small degrees, it’s important to keep in mind that the pH scale is logarithmic in a way that each whole number change is equal to a tenfold change from the previous integer. For example, a pH reading of 8 is ten times more alkaline than 7, but a reading of 9 is one hundred times more alkaline than 7. As a result, what might appear to be minor fluctuations can actually be large and detrimental.
Water source
Most of the time, high pH originates from your water source. The location as well as the form of filtration in your home plays a major factor. If you are using additives to manipulate your pH to accommodate certain fish species, keep in mind that the water still needs to be tested. It is not advisable to rely solely on what the bottle prescribes unless you are starting with reverse osmosis (RO) water, which presents a nearly perfect 7 pH starting point.
Plants and algae
The second most common cause is the presence of plants and algae. Since they survive on the process of photosynthesis, which involves consumption of carbon dioxide from the water, this contributes to a higher pH level. In the process, they also release oxygen which is important for the fish. During the night hours, when there is no light, the plants absorb oxygen and release carbon dioxide. This pH pulse generally tends to keep things relatively balanced, but it is worth monitoring. Remember this inverse relation: the more carbon dioxide in the water, the lower the pH, and vice versa.
Substrate
Low-quality gravel, sand or soil as a substrate may also serve to increase pH levels. Particularly limestone and dolomite can have this effect, due to their consistency of calcium carbonate. When choosing a substrate, it is important to find one that is appropriate for your species of fish so that the pH levels don’t risk an unhealthy rise.
How To Safely Lower pH In An Aquarium
If the pH levels are too high, it can cause fish to be unable to offload waste from their blood. This can cause stress and even death to fish, so it is important to monitor your water. Lowering pH to the appropriate level is a crucial factor to keep your fish healthy.
Knowing how to safely lower the pH of an aquarium, or to maintain it within the recommended range, will contribute to a thriving environment for your fish.
Regularly clean your fish tank
For the health of your fish, you should regularly clean your fish tank. This is vital to keep the water safe for them to live in, not only in reference to pH levels, but also to reduce the presence of algae and muck. Of course, you benefit from the cleaner appearance of your tank as well!
Learn more about: How To Get Rid Of Blue-Green Algae In A Planted Aquarium
Make Sure Your Filter Is Working Properly
A properly working filter is vital to a healthy fish tank. Filters work to cleanse the water of leftover food and fish waste. If the filter isn’t properly working, then excess food and waste can build up which can lead to increased pH levels.
Check Your Water
Check the water you are using for your tank prior to adding to the aquarium, thus allowing you to see what the pH levels are at the baseline. You can buy pH tests at pet stores and online. If you use tap water, it is important to treat it for the removal of chlorine, metals and minerals which may be harmful to the fish. Tap water often tests at higher pH levels. Consider using the API Tap Water Conditioner if you are using straight tap water.
Don’t Over Aerate Your Tank
Aeration refers to any process that increases the amount of oxygen. While this can have a small and temporary effect on pH, this is generally a less common cause of high levels. It is worth knowing about, however, because some processes of aeration may encourage a decrease in carbon dioxide in the tank, which subsequently increases pH.
Add Vinegar in Small Doses
A common way to lower pH levels is by adding vinegar to the aquarium, though this is only a temporary solution which will not permanently keep pH levels lower. The recommended dosage is about 1 mL of vinegar per gallon of the tank. Please note that this process works by increasing carbon dioxide in the water, which can harm fish if it happens too much all at once. Also, the absence of plants in the aquarium could also be a problem for the vinegar method, because the carbon dioxide will remain in the water content for much longer. The effect on pH is only 0.2-0.3, so this might be a useful option if you need to reduce pH while awaiting or preparing for a more permanent solution.
Add Driftwood and Peat Moss
Since driftwood is fibrous and coarse, it works to filter your water. It releases tannins which help keep the pH down.
Peat moss works similarly to driftwood to help filter your water. In addition, adding both driftwood and peat moss to your tank can add to its visual appeal. It is important to note that both driftwood and peat moss may change the color of your water for a few days.
Use Reverse Osmosis
A reverse osmosis machine can remove almost all of the contaminants in your aquarium that are causing pH levels to be high. The system allows small ions to pass through a barrier while holding back the large ions.
What Are The Symptoms Of Low pH In A Fish Tank?
What if the reverse is true, and the pH levels have dropped too low? The following examples are some of the symptoms that can occur as a result from low levels of pH.
Algae growth
If you notice the spread of green algae in your aquarium tank, this is the first sign that the pH level might be too low. This most often occurs due to increased amounts of available nutrients and light. This pollutes the water, making your fish more vulnerable to disease.
Lethargy
Your fish may start to appear uncomfortable, becoming slower in their movements and even gasping for air at the top or bottom. They can sometimes appear pale if the pH remains low for too long.
Death
A sad indicator that comes too late is the death of a newly introduced fish, while the old fish remains alive and seemingly healthy. Why might this happen? Old fish are accustomed to the current state of the water, while a new fish is not. Sudden large changes in pH levels are harmful to any fish.
Sludge and dirt build up on the bottom of the aquarium tank
Sludge most often occurs as a result of uneaten fish food that has accumulated at the bottom of the fish tank. This food breaks down in an oxygen-poor environment and turns into something that looks like mud or sludge.
The presence of too much sludge is not desirable as it prevents the flow of water, clogs the filter, and releases an unpleasant odor into the tank. A little bit is good for water quality, but too much can create problems and be a sign of an underlying pH problem.
What Causes Low pH In An Aquarium?
Lack of calcium
A lack of calcium, which is often found in limestone, dolomite and natural marble, can be a cause of pH that is too low. If any of these are used as a substrate, it is important to measure that the pH levels don’t go too high.
Faulty filtration system
Only a quality and powerful filter can keep your tank in good condition. Otherwise, your tank will have a buildup of fish waste at the bottom, as well as algae on its glass walls. This accumulation causes pH to fall, and therefore it is important to regularly clean the filter to keep it in good working condition.
Lack of plants
Since plants remove toxins and carbon dioxide from water, they help stabilize the pH of your aquarium water. It’s important to note that not all plants absorb the same types of substances from the water, so it is important to research the type of plants you choose to add if the pH level is a main reason for their addition.
Crowded aquarium
The bigger the crowd, the more food you will need to feed these fish daily. This will eventually result in more waste at the bottom of your fish tank. This waste is usually a source of ammonia and nitrite. This contributes to lowering the pH level of the water.
How To Safely Raise pH In An Aquarium
A natural way to raise pH in any aquarium in small increments is to add baking soda. You can increase the pH in the aquarium by using about 1 teaspoon of baking soda for every 5 gallons of water. Furthermore, adding shells, coral or certain types of rocks can do wonders for your tank’s pH. If you don’t like their appearance, you can put them in hard-to-spot places or a filter.
Here you can find more information about Adding Baking Soda To An Aquarium.
In a saltwater aquarium, Kalkwasser and some pH additives can significantly raise the pH level without excessively increasing the alkalinity, so long as they are added in very small doses followed by testing. Another way is to reduce the CO2 content. One good way to do this is by introducing macroalgae (whole multicellular algae plants) somewhere in the aquarium.
For all types of aquariums, you can also buy solution such as API pH Raising Solution specifically designed to raise the pH of aquarium water.
How To Test pH Levels in Aquarium Water?
Very simply, you can test pH levels with an inexpensive test kit. The most important thing is to choose the one that best suits your needs. Some require you to use tiny drops of liquid, while others require you to completely immerse the tester in the water of your tank.
A favorite liquid test kit is the API Wide Range pH Test Kit. Not only does this offer one of the more accurate testings, but it also has a wide range of results from 5.0 to 9.0. If the pH is high or low, this allows you to know better exactly how high or how low it is, and therefore what the best option may be to rebalance it.
If you’re interested in the color card test, the SJ Wave 7-in-1 Aquarium Test Kit is a popular choice which has the added benefit of also testing chlorine, general hardness (GH), carbonate hardness, nitrate, nitrite and temperature. While this is highly rated among customers, some agree that this method is less accurate than the liquid drops method of testing.
Conclusion
Understandably, the subject of pH levels can seem daunting at first; after all, we thought we were done with chemistry after high school! But it’s actually quite simple once you understand the acceptable range for your fish, the red flags to watch out for, and the solutions for rebalancing the aquatic environment if levels move out of bounds.
Start out by testing the water once a week. If you do not notice significant fluctuations after several tests, you might consider reducing testing to once a month; however, any time that you make a material change to the tank (replacing, adding or taking something away) make sure you are testing weekly for at least a few weeks.
The subject of pH is easily overlooked by new aquarists, but with the tools of knowledge provided here, you will be a master of your aquarium’s environment. Your fish will thank you!