If you have done any research about maintaining a healthy freshwater tank, you have probably read a great deal about pH and its effect on tank inhabitants. Not only does the pH level of your tank affect the water quality, but it can also …
In Part 1 of this two-part article you’ll discover some of the reasons why pH levels can drop in your aquarium and what you can do about it.
If you have done any research about maintaining a healthy freshwater tank, you have probably read a great deal about pH and its effect on tank inhabitants. Not only does the pH level of your tank affect the water quality, but it can also have an impact on the health and vitality of your fish. Many novice aquarium hobbyists experience problems with low pH or a sudden drop in pH in their tanks and, when this happens, they are at a loss what to do. If you are experiencing pH problems in your tank, it is wise to first identify the cause of the problem and to make the necessary corrections before taking steps to adjust the pH back to a normal level.
The Basics about Aquarium pH
The pH of your aquarium is simply a measure of how acidic or alkaline your tank water is and it is measured on a scale from 1 to 14. A pH value of 7.0 is neutral while values below 7.0 are considered acidic and values above 7.0 are considered alkaline. Most species of aquarium fish can tolerate a pH range from 6.5 to 7.5 but certain species like some cichlids are very sensitive to changes in pH and require a certain, stable level. Before you set up your tank for the first time it is wise to test the pH of the tap water you intend to use to fill your tank. The pH of your tap water may vary according to where you live and, depending on the species of fish you plan to keep, you may need to make adjustments to reach the ideal pH level in your tank. Once you have established the proper pH it is a good idea to monitor it with weekly water tests so you can catch any changes in pH before they become a major problem. It is not uncommon for aquariums to suffer a change or drop in pH and the sooner you take action to correct it, the less likely it will be to have a negative effect on your fish.
Causes for a Drop in pH
You already know that low pH values (values below 7.0) are considered acidic, so it makes sense that the pH level in your tank will drop following the addition of acids. Extra acid can make its way into your tank through several means — some are naturally occurring and some may be the result of a mistake on your part. Some of the naturally occurring causes of a pH drop include excess carbon dioxide, tannins from driftwood and the nitrification stage of biological filtration. Carbon dioxide (CO2) is the natural product of respiration, so the more fish you have in your tank the higher your CO2 levels are likely to be. The decay of plant matter can also increase the CO2 levels in a tank and many biofilters actually produce carbon dioxide. The best way to counteract high CO2 levels is to ensure that you have plenty of live plants in your tank – live aquarium plants utilize CO2 in the process of photosynthesis, using light as an energy source to convert CO2 into oxygen for respiration.
Another possible cause for a drop in pH is the leaching of tannins from driftwood or leaf litter. Driftwood is often used for décor in the aquarium trade because it provides cover for fish while enhancing the “natural” appearance of the tank. If you do not properly treat your driftwood before adding it to the tank, however, it can cause problems with your water chemistry. Driftwood contains tannins, or tannic acid, a natural compound occurring that stains water yellow or brown – tannins are responsible for creating “blackwater” habitats like the Amazon River. To prevent tannins from affecting your water chemistry, boil the driftwood or soak it for a period of several weeks before adding it to the tank. Boiling and soaking driftwood will help facilitate the release of the tannins, thus decreasing the chance that the driftwood will cause a pH drop in your tank.
In addition to excess carbon dioxide and tannins in the water, a pH drop may also be caused by the nitrification stage of biological filtration. Nitrification is the process through which beneficial bacteria in the aquarium convert ammonia to nitrite and then into nitrate. Ammonia is a substance toxic to fish, so the process of converting it into nitrate is extremely important for maintaining a healthy tank. During this process, however, your tank may experience a natural drop in pH as a result of the production of nitrite ions. Once your tank has properly cycled, however, it should establish a balance capable of counteracting this drop in pH to keep the water chemistry stable for your tank inhabitants.
Click Here for Part 2 of “What Are The Main Causes Of Low Ph In An Aquarium”
Maintaining stable water chemistry is the key to keeping your freshwater aquarium running smoothly and your tank inhabitants healthy. If the water quality in your tank decreases or your tank experiences a sudden change in water chemistry, your fish could become stressed and may even die. One of the most important aspects of water chemistry is pH and there are a variety of factors which may lead to a change or drop in pH. In addition to naturally occurring conditions such as excess carbon dioxide, tannins from driftwood and the nitrification stage of biological filtration, a drop in pH could also be the result of a mistake on your part as an aquarium hobbyist. Overdosing your tank on medications or adding the wrong kind of substrate can have a negative effect on the pH in your aquarium and, if you do not take quick action to remedy the mistake, your fish could suffer.
When it comes to selecting the substrate for your freshwater tank, you have many options to choose from. Standard gravel and aquarium sand are two of the most popular options, but some aquarium hobbyists are tempted to go a different route for the sake of being unique. Certain aquarium substrates like Oil Dri, Turface and Soilmaster have all been known to cause a drop in aquarium pH. If you plan to use any of these substrates in your aquarium, be aware of this possibility and consider mixing it with another substrate to balance it out. Another substance many aquarium hobbyists use as substrate in their tanks is peat moss — it is typically used as a fertilizer for planted tanks and is often covered with a layer of some other substrate to prevent it from staining the water. Like driftwood, peat moss contains tannins or tannic acids that naturally lower the pH of aquarium water. To avoid having problems with a drop in pH, be aware of the potential side effects of whatever type of aquarium substrate you choose. Standard aquarium gravel and sand are unlikely to have an effect on aquarium water chemistry, so if you are looking for a risk-free option one of these substrates may be your best choice.
If your aquarium experiences a sudden drop in pH it is wise to take quick action to remedy the situation before your fish come to any harm. Luckily, there are several simple ways to increase aquarium pH. One of the easiest ways to raise the pH in your tank is to add baking soda (sodium bicarbonate). Adding 1ml of baking soda per 10 liters of tank water can raise the pH as high as 8.2, so add the baking soda slowly and monitor the pH as you go so you can stop when it reaches the appropriate level. Another way to increase the pH in your tank is to add equal parts baking soda, Epsom salt and marine salt to the tank at a rate of 1ml per 10 liters of tank water. This mixture will not only raise the pH of your tank but it may also increase the water hardness, so exercise caution when utilizing this method to avoid hardening the water in your tank too much. Though this method is not recommended as a means of temporarily raising pH, the addition of calcitic gravel to your tank can also increase the pH. Not only does calcitic gravel increase aquarium pH, but it also increases the buffering capacity of the water so it is unlikely to drop below 7.5. If the fish in your tank require a neutral or slightly acidic pH, do not use this method to correct a drop in pH because it could raise the pH level too high.
Cleaning your freshwater aquarium does not need to be a daunting, time-consuming task. In fact, most of the maintenance tasks required to keep the water quality in a freshwater aquarium high will take only a few minutes of your time. Cleaning the substrate in your tank, for example, is a task made easy through the use of a gravel vacuum. Thanks to this tool, cleaning tank substrate can be combined with routine water changes and, depending on the size of your tank, generally takes only 15 or 30 minutes to complete. Because cleaning the substrate in a freshwater tank is so easy, there is no reason for you to avoid doing it. If you do not clean your tank substrate on a regular basis the water quality in your tank may decline as a result of excessive waste build-up. Poor water quality leads to stress in fish, which can then lead to a greater susceptibility to disease. In order to keep your tank clean and to protect the health of your fish, clean the substrate in your tank on a regular basis.
When it comes to selecting the substrate for your tank there are a variety of factors you need to consider. Not only should you think about which substrate you prefer, but you also need to consider your fish. The native environment of your fish may have a particular type of substrate, such as sand or gravel, so it is wise to perform a bit of basic research to find out before you decorate your tank. Before choosing a substrate, you should also consider which types are the easiest to maintain. If you do not mind putting in a little extra effort to clean the specialized substrates recommended for a planted tank, feel free to select something like fluorite or Eco-Complete. Since I incorporate live plants in my tanks, 
Gravel vacuums are the tool of choice among many aquarium hobbyists when it comes to cleaning the substrate in your tank. These tools are available in a variety of sizes and some models even come with attachments designed to reach into corners and underneath tank decorations. Select a gravel vacuum that is proportional to the size of your aquarium and to the amount of open space in your tank. If your tank is densely planted or heavily decorated, for example, you may need a gravel vacuum with a narrow mouth to avoid disturbing plants and decorations while cleaning the substrate. If you have a great deal of open space in your tank, however, a vacuum with a wide mouth will save time by allowing you to clean large areas of the tank at once.
Some gravel vacuums will connect directly to the faucet of your sink. The siphon-effect is created by simply turning on the water. While running water to create a siphon does waste a certain amount of water, many aquarium hobbyists prefer this method because of the convenience. Another method that offers some convenience is the fully-submersible battery operated vacuum by Eheim. While no water is actually removed from the tank, it does a good job of cleaning the substrate and has the added convenience of allowing a quick “spot clean” to remove the occasional uneaten wafer and small plant debris at the bottom of the tank. I really like the 
While using a gravel vacuum, pay extra attention to caves and other places where your fish like to hide because these places are likely to accumulate the most waste. If you have live plants in your tank, be careful not to disturb the roots while using your gravel vacuum. It is wise to leave a two-inch radius around the stems of live plants – live plants garner nutrients from organic waste so it is a good idea to leave something for the plants to feed on. If you have chosen fine-grained sand as the substrate in your tank do not drive the head of the vacuum into the sand – rather, move the vacuum gently above the surface of the sand to collect any accumulated waste.
Freshwater aquarium fish are living creatures and your fish tank is their home. As the owner, it is your responsibility to maintain a healthy environment for your fish and part of this responsibility involves cleaning the tank on a regular basis. Over time, solid waste, chemicals and uneaten fish food will accumulate in your tank, and unless you remove them, the water quality will deteriorate and your fish may become stressed or fall ill and die. You can avoid this consequence and keep your fish happy and healthy by performing a few simple maintenance tasks on a regular basis.
After removing the appropriate amount of water from your tank, replace it with fresh, de-chlorinated tap water. Chlorine and chloramine are chemicals commonly added to tap water to make it safe for human consumption, but these same chemicals are toxic to fish so they must be removed before adding water to your tank. The quickest method is to use a de-chlorinating solution. Simply pick up a bottle of de-chlorinating solution from your local pet store and follow the manufacturer’s instructions to determine how many drops or teaspoons to add per gallon of water. Another way to remove chlorine from tap water is to let the water sit in a large open container for at least twenty-four hours. The chlorine in the water will evaporate, making the water safe to use. Keep in mind that this method is only effective for removing chlorine, not chloramine. If your tap water is treated with chloramine you will need to use a de-chlorinating solution to safely remove it.
Use a clean sponge to wipe algae off the walls of your tank or check your local pet store for a magnetic algae scrubber that allows you to accomplish this task without having to get your hands wet. For stubborn algae, scrape the walls of your tank using a razor blade. If you use this method, be careful to avoid scratching the tank walls.
One of the worst mistakes you can make when cleaning your freshwater aquarium is to empty and clean out either the filter or the tank completely. The beneficial bacteria in your tank that help to maintain the nitrogen cycle live on the surfaces of your tank and also in your filter. If you empty out the tank or filter and clean them thoroughly you could kill the entire colony of nitrifying bacteria. When you refill the tank or filter you will be essentially starting over and the tank will have to cycle again in order to re-establish a healthy population of beneficial bacteria. If it becomes necessary to clean your filter, avoid scrubbing the entire thing. A quick rinse with water taken from the aquarium will suffice.
