So I started having some problems. It looked like a nitrogen issue relating to improper ph values.
I decided to change the substrate to a more appropriate brand (compo sana) and so I did a very careful transplant.
Things are looking better this week. it had a slowish start. a good flush with pH 6.3 could help in short term. Back off nutrients depending on soil make up maybe till spots improve. ppm of water feed compared to run off can indicate nutrient concentrations and take up. All the best