Cinderella 99 - V03

We have reached the fifth week and noticed that the plants of this cycle are developing more slowly than the plants of our last grow. We’re using the same setup, however we reuse (We flush it before) the last grow substrate and we think this may be the problem. The water that ran down the bottom was within the acceptable pH range, 6.22, but the PPM was above 900. Because of this, in our last watering we gave a lot of "pure" water at 6.2 pH and 74 PPM. After that we water with nutrients, a few days later we noticed an improvement in the leaves and a gain in growth speed. We will repeat this process on the next watering, measure the ppm and pH of the excess and continue to observe the plant's signs.