40х40 sativa first grow

On the 4th day, I became interested in why the plant was spinning so much and a friend told me that it could be a high pH. I measured and indeed the pH of the water I sprayed with was 7.8! I leveled to the 6.00 level and watered early in the day. By the end of the day, the plant stretched a lot (for 8 hours of night without light and 2 hours of light, at the time of the photo), I watered it a little with literally 5-6 ml of water and hope that everything will be fine in the morning. Because it seems to me that the leaves have turned yellow even more. After the stress with the overflow of high PH, I did not give anything for a day, the situation became better, but then I began to give too little water and on the 7th day there was again very strong stress.