What's up bro? I'm sorry to tell you that I can't be much help to you. I have never grown hydroponically, and when I did grow, which was several years ago, I didn't use any of that stuff. Light meters and PPM weren't things I needed to be concerned with growing outdoors. Al B. Fuct is pretty knowledgable about all aspects of growing. Maybe try to send him a message. If not, post a question and I'm sure you'll get the answers you need. Once again, sorry I can't help you.