Top up water for your Aquaponics system can come from several sources.
In this Tech Tip we will discuss Town or Municipal water.
Town or Municipal water should not need testing. Chemical analysis of your local municipal water is usually obtainable from your municipal water supply authority. A phone call to your water authority will often be enough for you to discover the important parameters.
Municipal water will contain chlorine or chloramine. These are added to kill bacteria and other living organisms, including fish, that may be present in the water supply.
Chlorine is easily gassed off by putting it into a holding tank, applying vigorous aeration for 24 hours.
Chloramine (NH2Cl) is commonly used in municipal water as an alternative to chlorine. Chloramine is much more stable and does not dissipate as rapidly as free chlorine. Chloramine is formed by ammonia and chlorine being combined. Some chloramines could readily form in Aquaponics system water if you were to add chlorinated water straight from the tap to an Aquaponics system tank that already carried some free ammonia. If you cannot get a report from your water authority and you strongly suspect the presence of chloramines, obtain a test kit that is able to test for "total chlorine" or "combined chlorine," not for "free chlorine." A test for "free chlorine" would misleadingly read zero in chloraminated water. (Skepticalaquarist.com 2014)
Chloramines can be removed from your source water by,
- Boiling and degassing. (not very practical for large quantities)
- Ultraviolet light. (Well established method of removal). (Adelstein, B 2013)
- Activated carbon filter. (pass the water through slowly)
- Commercially available de-chloramination products (some simply remove the chlorine, while others 'lock up' or detoxify remaining ammonia) (Skepticalaquarist.com 2014)
It is best to treat any suspect water in a holding tank before using for top up in the Aquaponics system proper.
More Teck Tips on water supply in following blogs.