Balcony Tent Grow

I think there’s been some sort of salt build up / nutrient lock. The lower leaves have been turning a lighter green and some even yellow on SL plants. Most stems are red. Seems like it’s a pH problem. I flushed them with 4-5 litres of water to reduce the nutrient concentration in the roots. Going to introduce molasses in next feeding! Organic Unsulphered And also stop the Micro (nitrogen)