How do I get the ppm level down in my water feeding?

Oh is this your runoff? I think I misunderstood. If so I wouldnt worry about it. I tested my runoff and it was 8000. I figured that my PPM pen is having issues because it has ran through the soil. My plant is perfectly healthy just like yours. I actually posted a question about it myself. I figured it was because it wasnt a super expensive one it wouldnt read it properly. If you're feeling a little uncomfortable with it, run double your usual watering amount through. So say you water 1L, water 2L. Run 1L plain PH water through. Then run 1L of your nute mix through. It will get rid of any built up salts etc. I did it with mine, my PPM is still super high though. I'm certain it's down to my TDS tester. I think you will be having the same issue. If not running the plain water through should resolve it 🙂