The pH value of the water
Overview
The pH value describes the acid-base level of the water. This is measured from 0 to 14. A pH of 7 is neutral and corresponds to pure water. Values below 7 are acidic, values above 7 are alkaline. A koi pond should be in the neutral area closely to a pH of 7. Too high or low values can be corrected e.g. by aeration, water exchange, or the addition of carbonate and acids.
Further information
Common
The pH (pondus Hydrogenii) represents a measure of the strength of an acid or alkali (base) in an aqueous solution. Scientifically defined, the pH is the negative decadal logarithm of the ion Oxonium activity.
The pH is usually measured in a scale from 0 to 14, although there are also negative values (<0) and values above 14.
A pH of 7 represents a neutral solution or absolutely pure water.
Values below 7 represent an acidic solution (-> acid)above values of 7 represent an alkaline solution (-> lye base)
pH 0-7 acid
pH = 7 neutral
pH 7-14 lye.
The further, the value is distant to 7, the stronger the acid or alkali is. A solution with a pH of 1 is a stronger acid than a solution with a pH of 3.
A Koi pond should be in the neutral range around pH 7. Slight deviations to a pH of 0.5 are tolerated if they do not occur suddenly, but can damage gills from a pH of 8.5. The pH should be measured regularly.
Factors influencing the pH value
In a pond, among others two factors determine the pH value: carbon dioxide and water hardness. These factors determine (buffering) the pH value.
Carbon dioxide:
Pure water absorbs when it rests, carbon dioxide from the air. The absorbed quantity can be,
temperature-dependent, up to 1 mg / litre. In solution with water carbonic acid emerges, the pH of the
water can lower down to 5. The aqueous solution gets acidic. By recirculation of the water the Carbon
dioxide can be removed of the water. You can see this when shaking a bottle of mineral water.
Plants and animals produce carbon dioxide. Through the light-driven photosynthesis, and the day time dependent throughput metabolism of living there will be a permanent change of pH in the pond, which fluctuates in a daily rhythm. Thus, in otherwise unaffected water, (e.g. no rain entry) in the morning, the pH value is the lowest, as during the night the Value is lowered by the increased content of the Carbon dioxide. These fluctuations, however, play a less important role in a well set pond.
Water Hardness:
The total hardness (earlier dH today Millimol calcium carbonate per litre) is the sum of the
concentrations of the cat ions of alkaline earth metals in water. The hardness of carbonate,
or the concentration of the hydrogen carbonate anion (kH) is part of the overall hardness and
the pH of the water is a crucial factor.
Today the water is divided in soft (<1.3 Millimol calcium carbonate per liter / <8.4 dH),
medium (1,3-2,5 Millimol calcium carbonate per litre / 8.4-14dH) and hard (> 2.5 Millimol
calcium carbonate per litre /> 14dH.
Generally one can say that a low concentration of alkaline earth ions is described as soft water, a high concentration as hard water.
The concentration depends on the quality of the introduced water.
The water hardness can be changed by chemical additions.
Other factors:
Organc acids:
We should mention organic acids, which are produced through bio-chemical processes such as nitrification and thus
influence the pH of the water.
Filled in water:
The pH of the pond is changed by filling with water (regional differences in water hardness).
Rainwater:
Rainwater by the environmental influences has to be classified in the acidic range (pH <7). Strong Entry therefore
moves the pH value of the koi pond in the acidic range.
Limits and Toxicity:
The pH should be in the neutral area at 7 if possible. Small fluctuations around pH 0.5 are tolerable. In the literature, there is found enough evidence that Koi feel comfortable at a pH of 8. However, at pH at 8.5 and hither it was reported about gill damage, neutral pH should be ensured. One should generally regard evidence as critical that the pH could be gradually adapted to values of 5 or 10. Increased aeration of the pond increases the pH. An addition of commercially available acids and carbonates and water to also regulates the pH.
