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Written by Webmaster
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Friday, 21 July 2006 |
Successful fish keeping involves regular monitoring of the quality of the water. Using certain chemical tests, the quality of the fish’s environment can be checked and then controlled so that their health remains optimal.
Test Kits use liquid reagents added to a 5 ml sample of water where the result is obtained by counting the number of drops added to the 5 ml sample needed for a change in colour to occur. Other tests are colorimetric, where the result is determined by the sample turning a specific colour and comparing this colour to a colour scale.
By regular testing you can make sure your system is in tip top condition.
An economical but essential pond accessory such as a multi test kit will help you monitor the water your fish live in.
Ammonia (NH4+)
Ammonia is released by most living organisms as part of the break down of organic matter. Fish waste contains a high level of ammonia, and they also secrete the substance at the gills.
Ammonia is very detrimental to fish health; it disturbs osmoregulatory function, irritates the gill and skin surfaces, destroys the protective mucous coating of the fish, causes internal and external bleeding, damages the brain and central nervous system. Even at levels below 0.01 ppm ammonia has been shown to depress the immune system of the fish.
The biological filter system of any pond breaks down this toxic waste ammonia by the action of Nitrosomonas Sp. bacteria converting it into less toxic Nitrite.
Thus it is essential to regularly check the concentration of ammonia using an Ammonia Test Kit, in your pond to ensure that the bacteria are functioning correctly and all toxic waste ammonia is being removed.
The ammonia concentration should always be zero in any system (unless just starting up).
It is especially important to check the ammonia level when a new pond is set up, as the bacteria that process this waste matter have not yet become fully established.
Ammonia is extremely toxic to fish, and should be removed from the water at all costs.
Zeolite chunks can be added to the filter system for instant removal of ammonia. Use 2kg/600 gallons of 20/30mm chunks. Recharge with strong salt solution.
Nitrite (NO2)
The toxic waste Ammonia secreted by the living organisms in the pond or aquarium is broken down by Nitrosomonas Sp. bacteria into nitrite, as part of the biological filtration process. Nitrite itself is not as toxic as ammonia but is still very detrimental to the health of the fish. The nitrite is converted into Nitrate by Nitrobacter Sp. bacteria.
As well as irritating the surfaces and gills of the fish the main factor leading to nitrite poisoning is the corruption of the structure of haemoglobin, the oxygen carrying agent of blood. Nitrite causes the addition of a methyl group to haemoglobin, forming methhaemoglobin which cannot carry oxygen, thus ‘asphyxiating’ the fish. This disease, called meth-haemoglobinaemia can be recognised as the fishes blood turns from red to brown.
To check the nitrite concentration of your ponds use a Nitrite Test Kit. The nitrite level of the water should always be zero. (Unless just starting up)
The appearance of any colour in this test indicates a warning that the filter system is not working perfectly.
pH Test Kits
The pH value of water indicates whether it is acid, neutral or alkaline, and this designation depends on the ratio of Hydrogen ions (H+) to Hydroxyl ions (OH-). Acid water has a greater proportion of H+, and Alkaline water has a greater proportion of OH-. Neutral water has equal amounts of the two.
Monitoring the pH value is extremely important to fishkeepers. Some fish have evolved in water that has a low pH (Around 6.0). Others have evolved in water with a very high pH (Around 9.0). The pH of water in a closed system such as a pond is not a constant value. There are many factors that can cause the pH to tend to rise (pH up) or drop (pH down).
1. As the living organisms in the pond or aquarium respire, they release carbon dioxide (CO2). This dissolves in the water as carbonic acid; pH down
2. The biological filtration system releases hydrogen ions and nitrate ions as part of the nitrogen cycle, which will lower the pH; pH down
3. If Plants or algae are present they will remove carbon dioxide during hours of daylight as part of photosynthesis; pH up. However at night this process stops, but the plants continue to respire producing carbon dioxide; pH down.
4. Pond concrete can leach into the pond water causing pH increases: pH up.
Thus it is extremely important to monitor the pH regularly as this value is influenced by many variables.
The pH is held constant and these fluctuations counteracted by the buffer system. Test the strength of your buffer using a KH test Kit (carbonate hardness of total alkalinity).
pH 4 - 10 is a broad range test kit for all types of pond. This test is available in a format specifically for pond keepers.
Nitrate (NO3)
Toxic waste Ammonia is broken down into Nitrite, by Nitrosomonas Sp. bacteria, and this is then broken down into Nitrate by Nitrobacter Sp. Bacteria. This process forms the biological filtration system and is called the Nitrogen Cycle.
Nitrate itself is relatively non-toxic, and will not cause troubles at low concentrations. However Nitrate can cause problems as the level rises;
1. Nitrate is a plant nutrient, thus the plant, and algal life in the pond or tank will consume it for growth, thus removing it from the system. High levels of nitrate can encourage excessive growth of algae and blanket weed in some circumstances.
2. Many fish keepers are starting to suspect that high nitrate levels may exert an influence on the efficiency of the immune system of the fish, and its health in general.
Monitor the level of nitrate in your pond using a Nitrate Test Kit on a regular basis. When the level becomes too high for your particular system perform a partial water change to lower the nitrate concentration.
If a high concentration of nitrate is present in your tap water, filter the water through a nitrate-specific ion exchange resin.
General Hardness (GH)
Water can be defined as either ‘hard’ or ‘soft’. The hardness of a sample of water is determined by the amount of ions it has dissolved in it. The General Hardness (GH) of a water sample is made up predominantly of Calcium and Magnesium ions. It can be measured in a number of ways.
Water hardness is very important for fishkeepers. Some fish live in very soft acid water, others live in very hard alkaline water. Water hardness and pH are inextricably linked, mainly because some of the salts that make up the water hardness also contribute to the alkalinity.
When water is too soft the buffering capacity is reduced, and the pH drops severely leading to acidosis (poisoning by acid water). If the water becomes too hard the pH tends to rise causing alkalosis (poisoning by alkaline water) in the fish.
Monitor the GH of your pond regularly using a GH Test Kit.
Carbonate Hardness (KH)
The Carbonate Hardness (KH) is extremely important in ponds. It stabilises the pH of the water. When the pH starts to drop, the buffer system uptakes the hydrogen ions that cause this decline. If the pH starts to rise, the buffer system donates hydrogen ions to the water to balance this change.
Thus it is important to have a KH value in the water as this prevents pH fluctuations which are lethal to the fish. Unless you are running a soft water tank, the ideal KH value is between 6 to 10 ° dH depending on the body of water tested. If it becomes too high the pH will rise, if it drops too low the pH changes cannot be counteracted.
The KH Test Kit is a titration reaction where the number of drops is equivalent to the strength of the buffer in German degrees hardness, ° dH, (one degree is equivalent to a hardness of 17.8 ppm calculated as calcium carbonate)
Test regularly to ensure continued buffer strength, and therefore consistent pH values. KH can be replenished by water changes in koi ponds.
Phosphate (PO4+)
Phosphate is an organic pollutant released into the water from decaying organic matter, especially from fish food and fish wastes. Together with nitrate, and potassium, phosphate is an essential plant nutrient (The N, P, and K ratio). Thus for pond plants to grow, a low level of phosphate is essential.
However the vast majority of ponds have a huge excess of phosphate which is surplus to the needs of the established pond plants. This excess level can lead to the growth of algae and blanket weed.
Monitor the level of phosphate in your system using a Phosphate Test Kit. When the level becomes too high, as indicated in the kit, perform a partial water change. If a pond has a consistently high phosphate level, and subsequent algae problems, use a filter media which absorbs phosphate out of the water.
Iron (Fe)
For pond plants to have lush and vibrant growth they need minute quantities of iron present in the water.
This iron is uptaken into the plant where it provides strength in the leaves and stems, amongst other beneficial effects.
Use an Iron Test Kit to ensure that your plant life is receiving enough iron, but remember that too much iron will lead to growth of unwanted algae.
Copper (Cu)
Copper is an excellent therapeutic agent for parasitic fish diseases.
When using a copper treatment such as Paracide it is important to get the therapeutic dose correct: 0.2 ppm for freshwater fish.
If this dose is too high the fish may itself suffer copper toxicity, but if the dose is too low then not all the offending parasite may not be killed
Thus when copper treating fish, use the treatment in conjunction with a Copper Test Kit to ensure precise dosage.
Calcium (Ca)
Calcium is essential in Koi ponds, where large and growing Koi, uptake calcium as a dietary mineral.
Many ponds soon become depleted, and thus need replenishment. Use a product such as Koi Care Activ-clarifier, which is a calcium form Bentonite clay, and has a variety of beneficial effects on the Koi pond.
Oxygen (O2)
Oxygen is essential for the fish, plants and filter bacteria of your pond or aquarium. The concentration of dissolved oxygen in the water can easily drop to levels that are dangerous to the fish by causing hypoxia stress. This can leave them vulnerable to diseases and in extreme cases cause death. Ponds with consistently low levels of oxygen can frequently become stagnant and unable to support life.
There are many factors that can influence the amount of oxygen that water can hold. In a pond the most critical is the temperature of the water. The warmer the water, the less oxygen it can hold.
Levels of oxygen can become low in ponds at night when the photosynthetic activity of the plants and algae stops, but they continue to use oxygen as part of normal respiration. Ponds with an excessive build up of detritus and sludge in the filters and substrate can become very oxygen-poor as the breakdown of this waste uses up large amounts of oxygen. Ponds can become very low in oxygen in hot, humid, thundery weather as the air pressure is very low so the gas exchange capacity at the water surface is greatly reduced.
Monitor the level of oxygen in your pond using an Oxygen Test Kit.
Low levels of oxygen can be improved by the addition of air pump and airstone.
In cold weather if ice forms on your pond ensure that a hole is maintained in the ice to allow toxic gases to escape.
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