Acidity & Alkalinity
PH is a system for measuring the free Hydrogen ions available within a given solution.
PH is described on a scale of 0 through to 14 where 7 is said to be neutral. Below 7 is considered acidic and above 7 is in the alkaline range.
In acidic water there is an abundance of negatively charged hydrogen ions but a smaller number of suitable molecules to bond with.
For alkaline water the chemistry is reversed as any free hydrogen is quickly bonded into larger molecules when available.
Neutral water is in a state of equilibrium where the acidic and alkaline reagents have balanced one another out.
In an aquarium, free hydrogen accumulates through the decay of fish wastes and other organic matter. Therefore most aquariums will gradually move toward a state of acidity as natural biological processes run their course.
Calcium carbonate based rocks and gravel are said to have a buffering effect which can keep the water in the alkaline range. This occurs as the components dissolve and bond with the free Hydrogen.
Thankfully applying pH to your aquarium does not require an intimate knowledge of chemistry. Most aquarium fish have a well documented pH preference.
It is common that a fish's requirements usually fall within the range of 6.5 and 7.5. To keep your aquarium inhabitants content it is a simple process of measuring and adjusting the pH of the water.
Determining the aquarium pH level is a simple procedure. Accurate
pH test kits are available for this purpose. Tablet based kits or litmus paper are suitable, but the most economical method involves a liquid reagent that is added to a water sample.
Bromothymol blue is the most common testing reagent in such kits. Such products will typically perform several hundred tests. After a few drops have been added to a fresh water sample the resulting colour is compared to a chart. By matching the colour and shade a reasonably accurate pH reading can be obtained.
Another testing option is an electronic
pH meter which provides
a reading on an LCD face
Changing the aquarium pH is a simple process of adding one of two chemicals. The manufacturer's instructions will not prescribe a set dosage however. Instead, the chemical is added and the water is retested until the desired level is achieved.
The two products used for this purpose are
pH up and
Such adjustment products are also readily available from pet shops. Some pH test kits will even include these adjustment chemicals as part of the package. Generally you will find yourself using alkalinity increase powders rather than acidifying agents. Therefore these package deals may not be the most economical choice in the long run.
Related Aquarium PH Pages
PH Products |
PH Test Kits |
PH Meter |
PH Up |
Aquarium Water Topics
Aquarium Water |
Aquarium Temperature |
Aquarium Heater |
Freshwater vs Marine |
Aquarium Calculators |
Aquarium Hardness |
Maturing An Aquarium