Calculation of EC Sample Calculation There are two ways to do this question, which includes a long way and a short way.

Appendix 5.2. Calculation of EC Sample Calculation There are two ways to do this question, which includes a long way and a short way. The long way involves determining the ppm separately for all the ions produced in solution and then adding up the totals. The short way involves determining the quantity in mg of each of the 4 major mineral salts used to make up the nutrient solution (FeEDTA and micronutrients stocks are not being considered due to their low levels), since each of these 4 compounds totally dissociate in solution. Thus,the same answer is obtained anyway. The example below shows the short way to do the calculation. “That is the concentration of KCl in ppm if 4 mls of a 2 M stock was diluted to 1 Liter (L) ‘? (a) Detennine the Molecular mass of KCl Molecular mass of K is provided in Appendix 5.1 , and see a Periodic Table to determine the Molecular mass of Cl. Molecular mass of KCl = 39.10 g/mole + 35.5 g/mole = 74.60 gfmole (b) Determinethe ppm KC] mineralsalt From Appendix 5.1 above, 8 mM KCI was used, Therefore: 8 mM KCl x 74.60 gfmole = 0.597 g/L = 597 nigfL = 597 ppm (c) Detennine the total concennafion of mineral salts in ppm Repeat the procedure above for the other mineral salts used in the nutrient solution ((1) Determinethe EC Using the total ppm value for all mineral salts combined, solve for EC using the equation EC = total ppm ionsi700