Chow_13answered grow question 4y ago If your in straight water your PH is at the top end of the range. You want to have it at 5.8. Keep it in the range of 5.5-6.5. EC seems a bit high for a plant that size. I think you got some nutrient burn going there. Or possibly some root issues with the light being able to shine through the holes of your net pot. Yes you should be changing the water weekly if you are running into issue or if your in flower.