Water hardness
Water hardness is often confusing and therefore overlooked by many aquarium owners. Water hardness is important because it is closely related to pH and, just like pH, fish have certain levels of water hardness that they thrive in, and if the hardness is too far off, it can cause stress and death. Water hardness can be most simply described as the level of mineral in the water. Hard water has a lot of dissolved mineral, and soft water has very little dissolved mineral in the water. The most common mineral in water is calcium, however, other minerals can also be present. Most people's tap water is either slightly hard or soft depending on where it comes from. Well water from areas that have a lot of limestone (calcium) is often hard. Water that comes from lakes (rainwater) is often devoid of mineral and is soft. It is important that you know the hardness of the water that you use in your fish tank. Some species of fish require hard water and others require soft water.
The other reason that hardness is important is that it affects pH. Hard water (high mineral content) is usually high in pH. Soft water (low mineral) is usually low in pH. The mineral in hard water will act as a buffer which will reduce the amount of acid in the water. The resulting water will be more alkaline and higher in pH. The problem arises when we try to lower the pH in hard water. If we add a commercial pH decreaser to an aquarium that is filled with hard water, the mineral in the hard water will buffer the water and make it difficult to successfully lower the pH. We would first have to remove the mineral from the water before we could effectively lower the pH. The same is true for trying to raise the pH in acidic water that is soft and does not contain much mineral. Until we add mineral to the water, it will be difficult to successfully alter and maintain a high pH level. So what do we do? Well, it is not too hard to add mineral in the form of calcium based rock, so making soft water hard and more alkaline (higher in pH) should not be too difficult. To soften hard water, you need to take the mineral out with a water softener, reverse osmosis or a specialized chemical that irreversibly binds up the mineral. Another option is to find a source of demineralized water for your fish tank.
Of course the alternative to all of this may be to tailor your fish and plant species around your existing water source. For beginning aquarist this may be the best solution. There are a wide variety tropical fish available and it is not difficult to find at least a dozen different species for every different type of water. Any decent book on aquariums and tropical fish will list the individual pH and hardness requirements of the different fish species.
Ammonia, nitrites, and nitrates
Ammonia, nitrites and nitrates are all part of the breakdown of waste in an aquarium. A significant amount of fish and plant waste can accumulate in any aquarium. Uneaten food, algae, and bacteria can also contribute to the waste load in an aquarium. As in all environments, this waste needs to be broken down and either eliminated or turned into something that can be utilized by another organism. In an aquarium there is a population of bacteria that is responsible for this process. The breakdown of waste is a four-part process.
- First, the waste from fish, plants, and food breaks down and releases ammonia.
- This ammonia is very toxic to fish and must be converted by bacteria to nitrite.
- The nitrite is also toxic to fish and must then be converted to nitrate.
- The nitrate is not nearly as toxic and is taken up by plants or algae and used to help them grow.
>> Continued on Page 3 <<
