Controllers
(NFT Hydroponic system Automation)
The nutrient solution in an NFT system is typically re-circulated through the root zones of plants 24 hours a day, 7 days a week.From the thin film of nutrient solution plants are able to uptake the various nutrients they require for their everyday growth and productivity.
Some plants do the bulk of their feeding during the day, while other plants take up a lot of nutrient during the cool hours of the night.
By maintaining a correct ppm or EC and pH level during the night and day, a grower is able to ensure that there is an abundant supply of nutrients which are readily available to the plants at all times.
If the preferred ppm or EC level for a particular crop is 1.2EC but the system often runs at 0.8EC because the grower is unable to be on site all the time to manually dose, then this will mean that there is a deficiency in the availability of nutrient at peak times when the plants require it most. Such deficiencies will result in slower growth, less uniform growth and plant growth characteristics that are commonly associated with nutrient deficiencies.
By installing an automatic
ppm or EC and pH Dosing controller, a hydroponic grower is able to take growing to a new level of professionalism and this investment will directly improve the quality and yield of their crop.
A dosing controller uses ppm or EC and
pH probes housed in a sample pot to monitor the strength of the re-circulating solution. The grower pre-programs the ppm or EC and pH setpoints that they want the hydroponic system to run at. The dosing controller the monitors the solution via the probes and automatically doses Nutrient A and B stock solutions and pH raise or lower solutions to keep the system running at the correct setpoints.
When ppm or pH values fall outside the setpoint range this indicates that the plants are feeding, or that fresh water has been added to the tank which then requires adjustment. The controller will immediately detect any change in the strength of the re-circulating solution and it will typically activate electric Solenoid Valves or Peristaltic Pumps to dose the stock solutions into the main mixing tank to adjust the nutrient strength so it matches the grower’s setpoint.
Once stock solutions are dosed into the mixing tank the controller goes on stand by while it monitors the change in the solution strength. This stand by period or “Dose Off” time ensures there is adequate mixing of the stock solutions into the nutrient solution. If, after a pre-programmed “Dose Off” period the solution strength does not change to match the pre-programmed setpoint, the controller triggers another “Dose On” period which adds more stock solution to the mixing tank. The “Dose On” and “Dose Off” times are measured in seconds and are adjusted to suit the size of the grower’s mixing tank and the flow capacity of the dosing pumps or valves they are using.
The use of an automated dosing controller will have the following benefits for a grower:
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ppm or EC and pH levels are maintained accurately 24/7 meaning that nutrient is readily available to the plants at peak times when they need it.
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Grower no longer has to spend time manually dosing and checking the strength of their nutrient solution, it is all done for them.
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More spare time to concentrate on other aspects of the business or to take a holiday.
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Greater accuracy with dosing
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More efficiency with dosing resulting in reduced fertiliser costs
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Faster growth times, greater crop quality and uniformity = More Profits
