De-chlorination should be a top issue for any pond keeper.
Chlorine, and its sister chemical chloramine, are commonly used in high concentrations in mains supply tap water making it safe for humans to drink. The level of chlorine used is safe for humans but causes harm to most aquatic life. As the majority of people will fill their brand new ponds straight from the hose pipe, de-chlorination is an important step in the pond building process and the chlorine levels most certainly need to be addressed before any fish are introduced.
The need to take chlorine out of the water doesn't stop once the pond is finished, de-chlorination should also be used whenever the pond water is topped up from the mains.
There are three main methods for removing the chlorine/ chloramine from the water:
Natural
Mechanical
Chemical
Natural
The chlorine will naturally leave the water as it is exposed to the atmosphere and it dissipates into the air. This will only occur where the water comes into contact with the atmosphere. Although the process will happen completely over time, most people cannot wait that long. This is therefore the major drawback for this method.
The process of allowing the chlorine to leave the water can be sped up by increasing amount of water which has contact with the air. This can be achieved by using a fountain pump which will increase the circulation of the water and ensure that water from the bottom of the pond comes to the surface. On the flip side if you don't want to bring the water to the surface you can always take the air to the bottom by using an air pump.
Pros: This treatment is free!
Cons: It takes a long time approx 6-8 weeks. It does not remove chloramines (which is a commonly used as a substitute for chlorine).
NB: To find out if your water contains chloramines you can request the information from your water supplier.
Mechanical
Chlorine and chloramines will be removed from the water if it is passed through high grade carbon. This can often be bought as an all in one carbon filter unit which is attached to your hose pipe.
Pros: This avoids adding any chemicals and is much quicker than allowing it to be removed naturally.
Cons: It can take a very long time to fill the pond as it causes the rate of water through the hopes pipe to slow down. They can also be quite expensive to purchase especially for very occasional use.
Chemical
There are lots of chemical treatments, such as our PondXpert Tap Tonic, which target the chlorine and chloramines and either remove them from the water or bind them up into harmless molecules. UV treatment will also help to speed the process up.
Pros: Treats both chlorine and chloramines, and works quickly in around 24 - 48hrs.
Cons: It can be expensive for a large volume.