pH is dropping, PPM is rising - overdose. When using coco, you need to water with a pH of 5.5-5.8. First, water well with clean water at pH 5.5, then charge it with a mix at 600 PPM and pH 5.6-5.7 and water with that mix for 3 days. After that, the pH will stabilize to 6.5-7.0 in the drainage.