Why Dechlorinate Tap Water For Hydroponics?
With hydroponics, there are two big issues with chlorine and chloramine treated water that growers need to take very seriously if they wish to achieve consistent, high quality yields. The first, if too much chlorine is present in water used for hydroponic farming, plant leaves will first turn yellow, then brown, and eventually the plant will die. This is called “chlorine toxicity”.
The second problem is when using helpful microorganisms such as beneficial bacteria and fungi, all must have chlorine-free water to survive and flourish. When utilized correctly, these tiny creatures help protect roots, increase nutrient uptake and directly affect the quality of and size of yields. Killing bacteria is a good idea for humans, but not necessarily when it comes to water for plants. And, since nutrient solutions are typically calibrated with purified water, the best way to maximize their benefits is to make sure water is chlorine and chloramine-free.
How To Dechlorinate Tap Water For Hydroponics
What is the best way to dechlorinate water for use in a hydroponic garden? Most people agree, the easiest and most efficient way is to simply purchase a dechlorination water filter. Dechlorinator filters remove the chemical before the water enters the hydroponic system.
These filters contain activated carbon, a porous material that condenses a large volume of surface area into a very small amount of physical material. A single gram of activated carbon is equal to up to 32,000 square feet of molecule-grabbing surface area! Millions of water treatment systems around the world use activated carbon for a number of reasons, all to ensure proper and safe water quality.
There are other methods to remove chlorine from tap water, such as:
- Leaving the water out in the sun
- “Bubbling” where forced aeration of the water oxidizes the chlorine over time
- Dechlorination tablets typically made of ascorbic acid, neutralize chlorine relatively quickly
- Even boiling the water works if no other options are available
However, carbon filters are the only method that doesn’t require extra time or the need for a holding tank.
The Time Intensive Methods
Off-gassing and boiling are relatively cheap methods for neutralizing chlorine in tap water but they take time. Off-gassing refers to the process of exposing water to sunlight which allows some forms of chlorine to evaporate over time, generally 12-24 hours. Using an aeration pump with diffusion stones will speed up the process. However, not all water treatment chemicals will off-gas and those that do will require more time at higher concentrations. Free chlorine will off-gas but chloramine, a chemical that has become more popular with municipal water treatment facilities in recent years, does not.
Boiling water will work but it also takes time. Boiling batches a few gallons at a time would simply not be practical. It would take significant time and energy to boil and cool enough water for a small size Lab.
The Cheap Method
Ascorbic acid, known commonly as Vitamin C, neutralizes chlorine and chloramine in tap water in short order. The process takes just seconds and is a part of our water treatment protocol at the Edible Learning Lab. A 5 gallon bucket of tap water can be treated with less than a teaspoon of ascorbic acid.
Ascorbic acid is easy to use, is cost effective, doesn’t lower dissolved oxygen in the water as much as other methods, dissipates quickly after application, and leaves nothing behind that adversely affects the quality of the water for plant or human consumption. This method of dechlorinating water for use with plants, specifically in the hydroponics system, is the best we’ve found and one that has proven viable in the Lab.
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