Why is water quality important?
The quality of the water in a pond or aquarium directly affects the health of the fish, as well as how clear and clean it looks. If the water becomes polluted, the fish will become stressed. This weakens their immune systems, leading to health problems. In fact, the majority of fish diseases are caused through poor water quality. By maintaining good water quality, it becomes much easier to look after a pond or aquarium.
How do I get my pH right?
Goldfish, pond fish, and most tropical fish prefer a stable pH between 6.5 – 8.5. This can be maintained through keeping the carbonate hardness (KH) of the water stable and above 3°dH (German degrees of hardness). A partial water change can be used to top up the KH level, and in aquariums Tetra EasyBalance can be added once a week to keep it constant.
How do I know if I have good water quality?
The only way to be sure that the water quality in your aquarium or pond is good is by testing it. Clear water can still be poisonous, and is no indication of health. By the time the fish show symptoms of poor water quality, damage has already been done. Therefore, getting into the habit of regularly checking water quality is important. This is easy with TetraTest and TetraPond 5 in 1 QuickTest strips, which check 5 water quality parameters in 60 seconds. For more detailed testing, use TetraTest and TetraPond liquid tests.
How do I reduce a high ammonia and/or nitrite level?
- Perform a partial water change, using tap water conditioned with AquaSafe. Repeat as necessary.
- Remove any excess debris from the gravel or base of the aquarium / pond.
- Limit feeding to once every day or two until levels return to zero.
- In an aquarium, add Tetra SafeStart to restore the filter bacteria and bring levels back down.
- Keep the filter running all the time; never switch it off for more than a few minutes.
- Never clean biological filter media (where the bacteria live) in tap water. Always use water from the pond or aquarium.
- Don’t add fish too quickly, as the bacteria that remove ammonia and nitrite need time to multiply and remove the ammonia they produce. Alternatively, make sure you add Tetra SafeStart whenever adding fish to an aquarium.
- Don’t replace the biological filter media all in one go, as this will remove all of the beneficial bacteria. Instead, replace part of it at a time. Some filters, such as those in the Tetra pond and aquarium ranges, have separate biological media, which does not need regular replacement.
How do I reduce a high nitrate level?
- Regular partial water changes with tap water conditioned with AquaSafe can dilute levels (provided levels are not high in the tap water itself).
- Submerged aquatic plants will naturally remove nitrate.
- Use a good quality Tetra food, as this will reduce waste production and therefore nitrate accumulation.
- In a freshwater or marine aquarium, use Tetra NitrateMinus for long-term nitrate reduction and control.
- Don’t overstock or overfeed the aquarium or pond.
Is water hardness important for fish?
Yes. Hardness refers to the level of certain essential minerals in the water. Carbonate hardness (KH) is important because it keeps the pH (acidity) of the water stable. Both KH and General hardness (GH) are also important for the health and vitality of the fish. Recommended levels for the majority of tropical, pond, and goldfish are 3 - 10°dH for KH, and 6 - 16°dH for GH. Some specialist tropical fish require specific water hardness values that may be higher or lower than these general recommendations.
What are the correct water quality parameters for keeping fish healthy?
You can check water quality using TetraTest or TetraPond kits. Recommended values for good health are:
- Ammonia = 0mg/l
- Nitrite = <0.3mg/l
- Nitrate = 25-50mg/l (higher values may be acceptable in a pond)
- pH = stable within the range 6.5 - 8.5
You can also check the following using TetraTest kits:
What are the most important water quality parameters?
There are lots of water quality parameters that you could test for, but the most important for a general pond, tropical community aquarium, or goldfish aquarium are as follows:
Ammonia - excreted by fish into the water; ammonia is poisonous and must be removed. If the filter is working properly, there should be no ammonia in the water. It is recommended to test for ammonia every week.
Nitrite - bacteria in the filter turn ammonia into nitrite, which is also poisonous. If the filter is working properly, this is also removed, and there should be no nitrite in the water. It is recommended to test for nitrite every week.
Nitrate - bacteria in the filter turn nitrite into nitrate, which is harmless to most fish. It is however an algae nutrient, and should be controlled if it gets very high. It is worth testing the nitrate level if you have a problem with algae in the aquarium or pond. Very low nitrate levels are only important for sensitive freshwater fish and marine aquariums.
pH - a measure of the water’s acidity. Fish do not respond well to rapidly changing pH levels, and therefore a stable value is important. Pond fish, goldfish, and hardy tropical fish require a stable pH between 6.5 – 8.5. Sensitive tropical fish and marine fish have more particular pH requirements.
Oxygen - like all animals, fish require a plentiful supply of oxygen. Because water contains much less oxygen that air, it is important to provide some form of aeration in an aquarium or pond. This usually means disturbing the surface with water flow from filters, fountains, waterfalls etc. Extra aeration can also be provided with air-pumps, such as the TetraTec APS aquarium air-pump range.
TetraTest kits are available for checking all these water quality parameters.
What is the difference between GH (general hardness) and KH (carbonate hardness)?
When measured with a TetraTest kit, GH primarily refers to the concentration of calcium and magnesium in the water, whereas KH refers to the concentration of bicarbonate and carbonate. GH is important for the general health and well-being of fish, and KH is important for maintaining a stable pH (acidity).
What is the nitrogen cycle?
The nitrogen cycle is a natural process, part of which is used in aquariums and ponds to keep the water healthy. It refers to the process by which harmful ammonia is turned into nitrite, and then nitrate, by bacteria living in the filter. These bacteria are called ‘nitrifying bacteria’, and without them we simply wouldn’t be able to keep fish healthy.
Why is the ammonia and nitrite high in my new aquarium or pond?
High ammonia or nitrite in a new pond or aquarium is not uncommon, and is commonly referred to as ‘New Tank / Pond Syndrome’. It occurs because the filter needs time to develop a population of ammonia and nitrite-removing (nitrifying) bacteria. When fish are added, they begin to produce ammonia. This rises until there are sufficient bacteria to remove it from the water. They turn this ammonia into nitrite, so this then rises until there are enough bacteria to turn it all into harmless nitrate.
If too many fish are added at once, or if fish are added too quickly, the ammonia and / or nitrite levels can rise to a point where they are dangerous to the fish. At this stage a water change must be done to dilute them. For this reason, traditionally it is recommended that new ponds or aquariums are stocked slowly, to avoid dangerous rises in these substances. Ideally, you should add a few fish, and then test the water every couple of days to monitor the rise and fall in ammonia and nitrite. Once it reaches safe levels, a few more fish can be added, and so on.
In aquariums, a faster and safer approach is to use Tetra SafeStart whenever fish are added. This contains the bacteria responsible for removing ammonia and nitrite, and thus biologically activates the filter much more rapidly. It allows the safer introduction of fish to new aquariums, and means you can add more fish to the aquarium at any one time. Simply add SafeStart at the same time as new fish are introduced.
Salifert Profi Test Kits
Salifert Profi Test Kits for reef, marine and advanced freshwater aquarists are some of the most precise and accurate test kits on the market. Kits are available for all aspects of the aquarium's chemistry, covering organic and inorganic pollutants as well as valuable marine trace elements to allow for accurate dosing when additives are required. The kits feature bold colour changes and good colour comparison charts and offer quick and easy water testing. There are 16 kits in the range, and most are suitable for both freshwater and saltwater environments (unless otherwise stated).