  The Nutrient Film Technique (NFT) method is one of the most popular
hydroponic cultivation methods. This method has advantages such as easier
maintenance, faster and optimal plant growth, better use of fertilizers, and
less deposition. The disadvantages of NFT include the consumption of electrical
power and the faster spread of disease. Therefore, NFT requires a good nutrient
control and monitoring system to save electricity and achieve optimal growth
and resistance to pests and diseases. In this study, a nutrient control was
designed with indicators of pH and TDS levels and equipped with an Internet of
Things (IoT) based monitoring system. The control system used is the Mamdani
Fuzzy Inference System. The output of the system is the active time of the pH
Up, pH Down, and AB Mix nutrient pumps, which aim to normalize the pH and TDS
of nutrient liquids. The experimental results show that one to three control
steps are needed to normalize pH. One control step has a response time of 60
seconds, and it can prevent pH Up and pH Down oscillations. As for TDS control,
the prediction of AB mix pump active time works accurately, and TDS levels can
be normalized in one control step. Overall, based on surface control,
simulations, and real experimental data, it is indicated that the control
system operates very well and can normalize pH and TDS to the desired normal
standard.
