Chlorine is a dangerous chemical for fish, alongside any Chloramines that are in your water. You will need to remove these chemicals before you put fish into your pond.
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. This level of chlorine is safe for humans but causes harm to most aquatic life. As most people fill their 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, this process should occur whenever the pond water is topped up from the mains.
There are three main methods for removing the chlorine/chloramine from the water. Please see the below for more information.
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 air. This process will naturally occurr over time (up to 8 weeks), but it is free. This process can be sped up by increasing contact between the water and the air. This can be achieved by using a fountain pump or installing a waterfall, which increases the circulation of the water. Alternatively, you can install an air pump to pump air into the pond.
• Pros: This treatment is free!
• Cons: It can take 6-8 weeks. It does not remove chloramines (which is a common substitute for chlorine). To identify if your water contains chloramines, please contact 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 a hose attachment. We currently sell three different dechlorinators: The PondXpert 10" Dechlorinator, the Evolution Aqua 12" Dechlorinator and the Evolution Aqua 30" Dechlorinator.
• Pros: This avoids adding 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 decreases the rate of water. They can be expensive to purchase, especially for very occasional use.
Chemical
There are lots of chemical treatments (like the PX Tap Tonic / Blagdon Fresh start) which will remove the chlorine and chloramines.
• Pros: Treats both chlorine and chloramines, and works quickly in around 24 - 48hrs.
• Cons: It can be expensive for a large volume of water. Large ponds also require good circulation when treatment is used to ensure thorough mixing.
If you need any assistance, please email us on info@pondkeeper.co.uk.