All hydroponic systems need some kind of reservoir to hold the water/nutrient solution, and they all need to have the reservoir water changed out and refilled on a regular basis. Since a hydroponic garden has no soil to get its nutrients and minerals from, it is always very important to keep your reservoir water clean and balanced. By keeping this in check, your plants will stay healthy and generally have fewer problems in the future.
When to change the reservoir water is really up to the individual grower and your specific preference. You generally want to change the water every two to three weeks, but your reservoir tank really needs to be checked every day for any problems or concerns.
In a hydroponic garden, the water levels decrease for two main reasons the water from the tank slowly evaporates into the air and the plants absorb some of it, too. This causes the water levels to drop a little every day. If the water level goes down too much, then the roots will eventually stop receiving the required nutrient solution if this happens, you will have big problems. It also causes the nutrients in the water to get more and more concentrated causing the solution to eventually burn the roots because of the nutrient intensity. If the water level drops too much before it is time to change it, then fill up the tank with straight water until the desired level has been achieved.
One suggestion would be to keep a constant record of how much water you actually add to top off the tank and when you did this. When the water youve been adding reaches the volume of half the tanks capacity, then change all the water out with fresh water and add in a fresh amount of the required nutrient solution, always paying specific attention to the correct quantity.
By following this suggestion for changing your reservoir, you will ensure a clean and healthy hydroponic garden. It is also a great starting point for keeping your system clean. You will eventually develop your own tips and tricks making the whole process simpler and more automated.
Here are some common symptoms which could indicate that the water needs to be changed:
The whole plant turns a light shade of green
The lower growth/leaves turn yellow
You may notice that plant growth is stunted
Change the water
Too Little Phosphorus
A plant turns a bluish green, or red and purple
Check the water and all other aspect of your water solution
Not Enough Nutrients in the Water
The plant looks malnourished and slightly drooping
The plant is pale green in color
The stems and branches are not so still
Change out the water in your hydroponic garden often – it is better to change the water out sooner rather than later if this symptom is occurring.