Water Quality
The water you use for your system is important as it will be used to transfer the nutrients to your plants. You will have to be careful to ensure the water you supply is adequate for proper plant growth.
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Our Aquaponic and Hydroponic systems are designed to recirculate water so there should be minimal need to add water as your plants grow. The water level will drop slowly over the course of time because of evaporation. The amount of evaporation will depend on the humidity level. If the humidity is high then less water will be lost because of evaporation and vice versa if the humidity is low.
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The following are variables normally considered in the Water Quality:
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Electrical Conductivity (EC)
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Total Dissolved Solids (TDS)
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Power of Hydrogen (pH)
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Hardness (KH)
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Ammonia
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Temperature
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Solids
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Note from Nomis Engineered:
As we build our business we will continue to experiment with different levels of water quality and bring you our findings so you have the latest information and can experience more efficient growth.
Electrical Conductivity (EC)
This is mainly used in Hydroponic systems to measure the strength of the nutrient solution . It is a measurement of the amount of sodium chloride (NaCl) in the water.
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For Hydroponics, see the nutrient solution instructions for recommendations on EC.
For Aquaponics, it is important to check the specific requirements of the type of fish used.
Total Dissolved Solids (TDS)
This is mainly used in Hydroponic systems to measure the strength of the nutrient solution . It is a measurement of the amount of minerals, salts, or metals dissolved in the water.
For our purposes we can directly relate this to the measurement of EC. To convert EC in milliSiemens/cm to TDS in ppm you multiply the EC by 1000 and then divide the answer by 2.
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For Hydroponics, see the nutrient solution instructions for recommendations on EC or TDS.
For Aquaponics, it is important to check the specific requirements of the type of fish used.
Power of Hydrogen (pH)
The pH level has an effect on many other variables in the quality of water. Fish, plants, and the process of nitrification all have required levels of pH so it is important to have the proper level based on your use. It is normally safe to operate the systems with a pH level of 7.
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The pH level refers to the concentration of hydrogen ions in a solution. This tells you if something is acidic or basic. The pH scale goes from 0 to 14 with values from 7 to 0 getting more acidic and values from 7 to 14 getting more basic.
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The recommended pH level range for growing microgreens is 5.5 to 7.0.
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pH levels can be adjusted with chemicals. When introducing chemicals into an Aquaponics system, it is important to verify that the type and amount of the chemicals will not harm the fish. Calcium hydroxide and potassium hydroxide are used in Aquaponics systems to raise pH. If the pH level is too high, that means that too much was added to raise the pH or that the water is hard. The nitrification process, which mainly grows the plants naturally, lowers the pH level. If the hardness is too high, it might take your system longer to start producing plants. This can be avoided by ensuring proper water quality when you start.
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The pH level can be measured by the use of a simple pH test you can find at the local pet shop or pool store.
Hardness (KH)
There are two types of hardness measurements. Most of us are familiar with general hardness which is mainly the measurement of calcium and magnesium ions in the water. For our purposes, we will explain the carbonate hardness (KH). KH is mainly the water's capability ("buffering capacity") to adjust the pH level and it is measured in dH (degree hardness).
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The KH level measurement can become important if you are trying to change your pH level. If the KH level is 4.5 dH or lower, it will be easier to change the pH level by adding a suitable acid to the water. Higher levels of KH could take more acid to lower the pH level, but this will also lower the KH level creating the possibility of the pH dropping lower than expected. Higher KH levels are beneficial when systems are at an optimal condition in the case you do not want the pH level to change much.
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The KH level can be measured by use of a simple pH test you can find at the local pet shop or pool supplies store.
Ammonia
Ammonia is important in both Aquaponic and Hydroponic systems. It is required to produce Nitrites which go through the nitrification process and feed the plants.
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In Aquaponics the ammonia is produced by the fish. In Hydroponics the ammonia is provided in the nutrient solutions.
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In an Aquaponics system, the ammonia level can be correlated to the relationship between the fish and plants. If the level is too high, then there are either too many fish for the number of plants or too few plants for the number of fish. A simple solution is to adjust the amount of plants being grown or fish raised. High levels of ammonia can also be caused by overfeeding the fish as the uneaten food can be transferred to the plants and keep then from being fed.
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In either an Aquaponic or Hydroponic system, the ammonia level can be related to the efficiency of the nitrification process which feeds the plants. For Hydroponics, the ammonia level can be adjusted along with the nitrate level to create a required ratio for specific plants.
Temperature
The temperature has an effect on many other variables in the quality of water. Fish, plants, and the process of nitrification all have unique required temperature ranges making it important to have the proper temperature based on your use.
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Normally a water temperature of 70°F is safe but can be different depending on the type of fish you are raising.
Solids
In Aquaponics, solids could be created by fish waste and/or uneaten fish food. This would normally require a bio filter (biofilter) if used on a large system but can be fixed by maintenance on the pump and pump bag. The pump will catch the majority of solids in the filter and the pump bag openings can capture some as well.
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Nomis Engineered offers services to refurbish used pumps along with providing instructions for the DIYs.
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If cycling through plants, it is recommended to clean the growing media as the nitrification process and/or uneaten fish food could hinder the production of future plants.