As Harbinger already said: this dark green does not look healthy.. that's a very high dosage of nitrogen, and if you say the run-off is 1500 ppm (i believe you take the Hanna scale), it means an EC of 3.0 which is way too high for most plants.. especially at this size. I suggest reading this: https://www.mandalaseeds.com/Guides/Fertilizing-Smart-Guide
30.9 degrees is also too hot, so try to get the temperature down, and preferably the humidity up (60 to 70%)