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Koi benefit significantly from stable water conditions, this is especially true for pH which must remain consistently between pH7 and pH9
pH is one of the most widely used and quoted tests and should regularly show a slightly alkaline pH ( above 7.4pH ). However, several factors can cause the pH to fluctuate either side of this desirable band with adverse effects on koi health. If pH levels do tend to fluctuate wildly, it is critical for the long-term health of your koi that you try to identify some of the likely causes of these swings with a view to preventing them in the future.
1. What if my pH is greater than 9.0?
This stressful highly alkaline water can cause fish to gasp at the surface, and if experienced long term, will stimulate fish to secrete excessive amounts of a mucus on the skin.
A likely cause of a high pH is the introduction of a highly alkaline substance such as run-off from new or untreated concrete or cement work. Builder's lime (calcium hydroxide) is an extremely caustic substance, and if left exposed or untreated on brickwork around the pond may cause the pH to rise rapidly.
There are ways of preventing this problem from happening.
Paint all concrete/cement work with a sealant. A very effective, easy to use transparent and colourless sealant such as G4 can be painted onto surrounding rockwork. If used on a waterfall, it has the added benefit of waterproofing the feature. As the pond water does not come into contact with the alkaline lime, then the pH of the pond water will remain unaffected.
2. What if my pH drops below 7.0 and becomes acidic.
If pond water has the chance of becoming acidic then problems can accelerate very quickly within the pond and lead to dramatic changes in koi health. It is interesting to note that the symptoms shown by koi suffering from a low pH are very similar to those when experiencing a very alkaline pH.
The most likely cause of a low pH is the neglect of water changes. The overall effect of biological processes such as respiration and particularly bio-filtration is to cause the pH to drop.
Preventing a drop in pH.
There are two ways, if used together, that will prevent an unhealthy drop in pH and help to maintain a better overall water quality.
A. Addition of a buffering material.
By adding crushed shell or lithaqua to a filter, the pH can easily be prevented from dropping below pH7. The calcium carbonate in these buffers will 'mop up' the acid-causing hydrogen ions, thereby preventing the pH from dropping. A simple, cheap and effective means of maintaining a stable pH. 'Every pond should have some'.
B. Regular partial water changes.
These should be carried out to dilute the build up of waste from the koi’s metabolism and bio-filtration. A partial water change will reduce this and as most tap water is buffered by water companies to become alkaline, this will automatically add more stability to the pH. Some areas have a very low buffering capability in the source tap water so kH should also be monitored.
NB. When adding any water to a pond it is better to pass it through a purifier first to eliminate the added chloramines. You can not change the source water so checking this first to see what its readings are helps when checking the pond water.
pH is one of the most widely used and quoted tests and should regularly show a slightly alkaline pH ( above 7.4pH ). However, several factors can cause the pH to fluctuate either side of this desirable band with adverse effects on koi health. If pH levels do tend to fluctuate wildly, it is critical for the long-term health of your koi that you try to identify some of the likely causes of these swings with a view to preventing them in the future.
1. What if my pH is greater than 9.0?
This stressful highly alkaline water can cause fish to gasp at the surface, and if experienced long term, will stimulate fish to secrete excessive amounts of a mucus on the skin.
A likely cause of a high pH is the introduction of a highly alkaline substance such as run-off from new or untreated concrete or cement work. Builder's lime (calcium hydroxide) is an extremely caustic substance, and if left exposed or untreated on brickwork around the pond may cause the pH to rise rapidly.
There are ways of preventing this problem from happening.
Paint all concrete/cement work with a sealant. A very effective, easy to use transparent and colourless sealant such as G4 can be painted onto surrounding rockwork. If used on a waterfall, it has the added benefit of waterproofing the feature. As the pond water does not come into contact with the alkaline lime, then the pH of the pond water will remain unaffected.
2. What if my pH drops below 7.0 and becomes acidic.
If pond water has the chance of becoming acidic then problems can accelerate very quickly within the pond and lead to dramatic changes in koi health. It is interesting to note that the symptoms shown by koi suffering from a low pH are very similar to those when experiencing a very alkaline pH.
The most likely cause of a low pH is the neglect of water changes. The overall effect of biological processes such as respiration and particularly bio-filtration is to cause the pH to drop.
Preventing a drop in pH.
There are two ways, if used together, that will prevent an unhealthy drop in pH and help to maintain a better overall water quality.
A. Addition of a buffering material.
By adding crushed shell or lithaqua to a filter, the pH can easily be prevented from dropping below pH7. The calcium carbonate in these buffers will 'mop up' the acid-causing hydrogen ions, thereby preventing the pH from dropping. A simple, cheap and effective means of maintaining a stable pH. 'Every pond should have some'.
B. Regular partial water changes.
These should be carried out to dilute the build up of waste from the koi’s metabolism and bio-filtration. A partial water change will reduce this and as most tap water is buffered by water companies to become alkaline, this will automatically add more stability to the pH. Some areas have a very low buffering capability in the source tap water so kH should also be monitored.
NB. When adding any water to a pond it is better to pass it through a purifier first to eliminate the added chloramines. You can not change the source water so checking this first to see what its readings are helps when checking the pond water.