A. Relationship between EC and Nutrient volume Prior to this experiment, both of pumps need to be calibrated to calculate the relation of EC value between nutrient volumes into different volume of water inlet. The calibration result (Figure 4) shows the linearity of EC value and fertilizer volume even with different water inlet volume. This test was purposely done to find the interrelation between both inlet water volume and nutrient volume to the desired EC value although different volumes of diluted water inlet was supplied and to find out the value of factor a depending on the composition of the particular concentrated solution, a as in equation (4). From that, by substituting a factor and the water volume, Vw to nutrient dilution volume, Vn ratio, Ai, the final desired EC is derived by