Which water can I use to fill the pond?

The water to fill the pond can come from the aqueduct, from a well, from a stream, from a water spring, from a rainwater collection tank, or directly from the rain (albeit very slowly).

If you have the chance of drawing water from a river, from an irrigation canal, or from the rain, it is certainly an excellent solution.

Most people use aqueduct water to fill the pond, and usually this water does not present any problems.

A question I am often asked is whether chlorine can be harmful to aquatic plants. Chlorine is certainly harmful, but for the concentration used in potable water it is not a problem, as the chlorine evaporates in a short time after filling the pond.

Aqueduct water is kept under control and usually it has parameters in a certain range. However, there are areas where potable water is very hard, i.e. it contains an excess of minerals and limestone.

Considering the thousands of customers of our nursery, I can say that generally aqueduct water does not cause survival problems for aquatic plants, but there are exceptions.

So it is recommended in any case to do a water test to measure the parameters of pH, carbonate hardness, total hardness, and adjust them, if necessary.

If, on the other hand, you take the water from a well or from a private water spring, it is common to find abnormal parameters and therefore a water parameter test is a must.

The most frequent abnormal values found in well water are too high pH and too high hardness (excess of limescale).

You can check these parameters for a few euros by purchasing the Tetra 6in1 Test, which is a quick test with cards that change colour on contact with water, and measures: pH, carbonate hardness (KH), total hardness (GH), nitrite (NO2-), nitrate (NO3-) and chlorine (Cl2).

You must also consider that this water test is not complete, as there may also be excess heavy metals in the water. In some well waters located only a few kilometres from the sea, you may also find slightly salty water, which is obviously harmful to plants. Therefore, to get a 100% complete test, you should do a more in-depth analysis.

Another aspect to be aware of is the issue of rainwater collected from the roofs of houses and stored in the tanks.

You have to consider that the water may run into gutters and copper pipes (and copper is harmful to aquatic plants and fish), or it may be stored in iron containers (excess iron in the water promotes algae).

Finally, you must also take into consideration the material the pond is made of.

Typically, ponds are made with PVC or epdm liners, which are specially designed for waterproofing ponds.

There are also those who build concrete ponds and then use paints or other waterproofing products. You must be aware that these products often release toxic substances for plants and fish or alter the pH values of the water.

If you build a concrete pond or a rainwater collection tank, make sure you use products that are completely non-toxic and compatible with potable water.

For optimal plant growth, the pH must be between 6.5 and 8 at the most.

The total hardness (GH) must be between 6-16°dGH and the carbonate hardness (KH) must be between 5-10°dKH. Higher values indicate a water hardness that is too high and therefore harmful to plants.

Over time, we have selected plants that can tolerate situations that are also somewhat borderline, so in the case of the Easy Pond Kits or in the case of the Pond Consultation, by providing as much accurate information as possible, we can help you achieve a good result anyway.

If the values deviate greatly from the optimal ones, we always endeavour to choose the most suitable plants for the context, but rooting cannot be guaranteed.

If you choose plants from our website by yourself, it is your responsibility to read all plant data sheets thoroughly, and you bear the risks if you choose plants that are not suitable for your water characteristics.

Here are some tips if the water parameters you want to use to fill the pond are abnormal:

• You can wait some time so that rain and thunderstorms dilute the original water a little at a time.
• If your well water is too hard, or contains too much iron, or has other anomalies, you can use other water for the initial filling (such as rainwater, water from the aqueduct, or from rivers or irrigation canals), and then you can only use the well water later to top up the evaporating water. By the way, in the meantime the pond water will also be mixed with rainwater.
• If you use limescale-rich well water in your home, as well as for the pond, you can consider installing a water softener, so that even pipes, washing machines and dishwashers will not have problems over time.

In general, water parameters can be adjusted rather easily:

• If you want to reduce the pH of your pond, there are products called pH minus, based on sodium bisulphate. pH minus works by simultaneously lowering the carbonate hardness (KH) and the pH. Any product should be applied according to the dosage and instructions on the label and it is best to apply it in several stages, on different days, to avoid causing problems for plants and fish.
• If you want to reduce both pH and total hardness (GH), you can put (acid) peat in the pond, naturally containing it inside fabric bags such as jute to avoid dirtying the water, or you can mix it with the soil you use for planting plants in micro-perforated baskets. There are also specific products based on peat conglomerates that do not dirty the water.

This article is also available in Italiano – Deutsch – Français – Español