Water quality and water values in the pond

Water Quality

It is quite possible to get and keep your pond in balance without a pond pump or filter, but especially without measurements and water tests.

Simon van der Velde

You read more and more often that you are advised to test the water of your pond for KH, GH and PH values. Do not be tempted to buy all kinds of measuring equipment and water improvers. None of this is necessary: if your fish are swimming nicely and the plants are growing nicely, then the water in the pond is of good quality. Those are the indicators!

Simon van der VeldePond specialist and aquatic plant breeder

Pond expert package

Tip from Simon: Bacta Clear + Oxygen Plants.

Oxygen plants are essential to any pond. They filter the water, reduce algae by blocking sunlight and remove the need for a pump or filter. In addition, they offer fish protection from danger. All of our hardy oxygen plants come with a 100% growth and flowering guarantee from our own nursery.
Clear pond package
pond advice book

Want more helpful tips?

Learn about common mistakes and get a handy planting plan, along with plenty of valuable tips in Simon's Pond Advice Book.
Simons pond advice book

35 years of expertise

1000+ constructed ponds

1000+ satisfied customers

Frequently asked questions about water quality and water values

Pond Advice

When talking about water hardness and measuring it, many people will initially wonder what it is. Water hardness can literally be translated to the hardness of the water in the pond. It is often recommended to measure the water in the pond for hardness, 3 water values are then tested: The total hardness (GH value), the carbonate hardness (KH value) and the oxygen level (pH value). But what many people don't know is that you don't need to measure the hardness of your water at all if the pond is set up properly.

The ideal hardness of the water in your pond is determined by the combination of the GH value, KH value and the PH value. Water values and therefore hard water is expressed in DH, which stands for German Hardness degrees. The correct hardness of water is between 8 and 12 DH. So this can be seen as ideal water hardness.

Pond water values today can be measured in a variety of ways. There are all nice values established for it, making it clear when the quality and hardness of your water is good. But did you know that measuring and keeping your pond water between the desired standards is a difficult or even almost impossible task. This is due to the changing weather conditions we face. This means that 24 hours after measuring, the water in your pond can look completely different again. For this reason it is not realistic to always keep your pond water within these standards. But what is the solution? Well there I have the perfect answer, I have namely a pond construction roadmap which describes exactly how you your pond by adding the right amount of substrate, oxygen plants and pond bacteria healthy without having to monitor the hardness of the water.

To get your pond clear, or better yet, to keep it healthy from construction, you can follow some steps that are guaranteed to lead to success, provided you follow the steps correctly, of course. In fact, it is not at all necessary to measure the hardness of your water or to soften the water in your pond. People often talk about lime in the pond but this problem does not arise when the pond is set up correctly, i.e. with substrate, bacteria, oxygen plants and so on.

Water hardness 1 means that there are 17.8 grams of lime in the water per 1,000 liters of water. The average hardness of water is between 8 and 12 DH. When the water in your pond is between 0-4 DH it means that your water is very soft, a water value between 4-8 means that your water is soft, between 8-12 means that the hardness of your water is average and a water hardness between 12-18 DH means that your water is quite hard. A DH between 8-12 is ideal.

Advice on pH value, gH value, kH value pond

Measuring water values is not necessary if you provide your pond with what it needs. We like clear water without the addition of chemicals. Read what to do if the KH, pH and GH levels are not up to standard in your pond.

Keeping the water in your pond clean and clear seems to be quite an art. Water values fluctuate and so it is constant work for the small biotope that is your pond. Yet it is possible to get and keep your pond in balance without a pump or filter, but especially without measurements and water tests. At Van der Velde aquatic plants we like to make pond water clear in a natural way.

Ideal water hardness does not exist

A beautiful, clear pond full of healthy aquatic plants and all kinds of insects and animals that come to visit the water; it is the wish of many pond owners. Such a pond is within reach without having to measure the pH, KH or GH levels in the pond every so often. The ideal water hardness does not exist; after a rainstorm or a day full of sunshine, the values are completely different again. Water values in the pond fluctuate continuously. In our opinion measuring is not necessary, and don't let anyone tell you that you need all kinds of remedies to get your pond in biological balance. You will be advised an expensive test and then all kinds of remedies to improve the water parameters. But we don't do this in nature, so not in your pond either. Rather help nature by adding extra pond plants, such as oxygen plants or water lilies. What does your pond need for good water parameters? We explain.

KH value pond; carbonate hardness

KH stands for carbonate, KH value for carbonate hardness. The amount of carbonates in your pond affects the health of the pond water. Too many carbonates will cause algae to find a food source and grow. To prevent this, it is important that bacteria and enzymes are present in the pond water that provide enough CO2 for the pond plants present. If you add these bacteria to the water when starting up the pond and every spring and fall thereafter, the KH level will be balanced. A layer pond substrate on the bottom ensures that these single-celled organisms can settle well in your pond.

PH value pond; acidity

The acidity of the pond is indicated by the pH value. The more acidic the water, the worse it is for pond animal life. Less CO2 is present in acidic water, which makes growing difficult for oxygen plants in particular; there is a lack of nutrients. A pond that is in biological balance therefore contains not only enough bacteria and enzymes, but also (plenty of) pond plants. The bacteria release CO2, the pond plants absorb it and release oxygen in its place. To keep the water parameters good, we recommend at least 1 basket (with 4 plants) of pond plants per 1 m2, but this can also be double or triple.

GH value pond; water hardness

The GH value of pond water indicates the hardness of the water. This means the level of minerals (mainly calcium, magnesium and potassium) found in the water. Oxygen plants in particular need the minerals to grow. A higher GH value means harder water, which is beneficial for your pond plants and unfavorable for algae. Hence, adding pond plant clay, which is high in minerals, to the water feature will help fight algae, but also provide your aquatic plants with sufficient nutrients.
Tips, advice and substantial savings
I would like to share my experience with you, and advise you to solve any pond problems and reduce pond maintenance. As a result, you can easily save hundreds of dollars.
Tips, advice and substantial savings
I would like to share my experience with you, and advise you to solve any pond problems and reduce pond maintenance. As a result, you can easily save hundreds of dollars.
Tips, advice and substantial savings
I would like to share my experience with you, and advise you to solve any pond problems and reduce pond maintenance. As a result, you can easily save hundreds of dollars.
Tips, advice and substantial savings
I would like to share my experience with you, and advise you to solve any pond problems and reduce pond maintenance. As a result, you can easily save hundreds of dollars.
Oxygen plants are a must for any pond!
Sufficiently oxygenating underwater plants in the pond means you will NOT need a pump and filter. Oxygenating plants filter the water and block the sun. This causes the water to heat up less which reduces the formation of algae. Oxygen plants also provide shelter for fish from impending danger. All of our oxygen plants are hardy and are supplied from our own aquatic plant nursery with a 100% growth and flowering guarantee. For oxygen plants, I recommend a minimum of 10 to 12 individual plants per m³ (1000 liters of water) and 2 baskets of 4 plants per m². The amount needed depends on how quickly you want the pond to balance and your visual requirements.
Pond specialist & aquatic plant breeder
Simon van der Velde
Loose oxygen plants
Ideal for the deeper part of the pond.
Recommendation: 10-12 plants per 1,000 liters of water
Baskets of oxygen plants
Suitable for shallow areas, provide natural elevation differences and help prevent algae.
Recommendation: 2 baskets per 1 m²
Oxygen plants are a must for any pond!
Sufficiently oxygenating underwater plants in the pond means you will NOT need a pump and filter. Oxygenating plants filter the water and block the sun. This causes the water to heat up less which reduces the formation of algae. Oxygen plants also provide shelter for fish from impending danger. All of our oxygen plants are hardy and are supplied from our own aquatic plant nursery with a 100% growth and flowering guarantee. For oxygen plants, I recommend a minimum of 10 to 12 individual plants per m³ (1000 liters of water) and 2 baskets of 4 plants per m². The amount needed depends on how quickly you want the pond to balance and your visual requirements.
Pond specialist & aquatic plant breeder
Simon van der Velde
Loose oxygen plants
Ideal for the deeper part of the pond.
Recommendation: 10-12 plants per 1,000 liters of water
Baskets of oxygen plants
Suitable for shallow areas, provide natural elevation differences and help prevent algae.
Recommendation: 2 baskets per 1 m²