Optimal water parameters for healthy pond life

Would you like to enjoy your pond throughout the year? To keep all the fish, other living creatures and plants in the pond healthy it is a must to regularly measure the water quality of your pond. Water quality is determined by a number of different water values: acidity (pH), carbonate hardness (kH), joint hardness (gH), ammonia, nitrite and nitrate. In this blog you will read all about the ideal water values for your pond.

Why is measuring water values so important?

You probably already use a pump, filter and UV-C device to prevent your pond water from turning green. However, checking the water quality should not be forgotten when maintaining your pond. Because a garden pond is home to more diverse fish and other living creatures than in the wild, a helping hand is needed to achieve a healthy balance. If you don’t, algae growth will occur, your fish will get sick or aquatic plants will not grow sufficiently.

Regularly measure for optimal conditions

We recommend regularly, preferably weekly, measuring the water quality. In certain situations extra control is necessary, for example when you have many fish or if you notice that the pond water is not balanced. Water values can easily change, for example due to refilling with tap water, changing weather conditions, fish excrement and leaves that have ended up in the pond. It is better to check too much once than too little. You measure the water values using test strips, drip tests or electronic measuring devices. That sounds like a lot of work! Yet this is not bad, with the Aquaforte test strips you within a minute view of the water quality of your pond.

The optimum values for your pond

What are the main values that you should check and what numbers belong? We have listed them here for you. Want to know more about the values, please read on.

  • pH: 6,5 – 8,5
  • KH: 6° – 10° dH
  • GH: 8° – 12° dH
  • Ammonia: 0 mg/l
  • Nitrite: 0 mg/l
  • Nitrate: <30 mg/l
  • Phosphate: <0,03 mg/l

Acidity (pH): 6,5 – 8,5 This value affects the well-being of your plants and fish. The value should be between 6.5 and 8.5.

Carbonate hardness (KH): 6-10° dH Carbonate hardness (KH) is also known as temporary hardness. KH serves as a buffer of pH; the KH stabilizes the pH, so to speak. Nitrifying bacteria consume KH when converting ammonia into nitrite and nitrate (1 part ammonia costs 7 parts KH). When the KH falls below 3° dH, the nitrification process stops.

Total/joint hardness (GH): 8-12° dH The combined hardness of the water is determined by calcium and magnesium. For the growth of aquatic plants, it is very important that the GH is not lower than 8° dH.

Ammonia/Ammonium: 0 mg/l Fish secretions and organic matter decomposition cause ammonium to enter pond water. If the pH value is too high, ammonium is converted to ammonia, which is toxic and causes health problems in pond life. Therefore, this value should be 0. Ammonia is already harmful at 0.1 mg/l. Bacteria convert ammonium to nitrite.

Nitrite: 0 mg/l Nitrite results from the decomposition of ammonium. Nitrite is less toxic than ammonium, but can also cause health problems in the pond. The nitrite value in the pond should therefore also be 0. Bacteria convert nitrite into nitrate.

Nitrate: < 30 mg/l Nitrate is not toxic, but it is considered an undesirable substance in the pond. Up to 100 mg/l, it is harmless, but it is a food source for algae and inhibits the growth of small fish. In addition, it increases stress in fish. Bacteria convert nitrate into nitrogen gas (N2).

Phosphate: < 0.03 mg/l Less important for fish ponds, since floating algae are treated with UV-C and filamentous algae are often controlled with pesticides. For ornamental ponds/swimming ponds, phosphate levels are preferably below 0.03 mg/l to control algae growth.

Correcting the values

Have you measured all the values? Perhaps your pond is in tip-top shape and no action is required. However, there is a good chance that you need to work on restoring the natural balance in your pond. You now know which values need to be corrected. Correcting is easily done by adding water treatment and water improvement products to your pond water. This way you keep the aquatic life in top condition and enjoy your pond all year round.

Here you can read more about maintaining your pond.