Hey there, you're probably right, most of the time these household fertilisers dont have the NPK ratios you're looking for. What i'm seeing is also a magnesium deficiency you can tell from the yellowing between the veins and the "burning" on the sides of the leafs. Probably because of the light/heat or maybe even because plants use Magnesium to regulate nutrient uptake. I would try to get some flowering ferts with low N and high PK as well as some calmag (never grow without calmag!) which you should add to your feed regularly as well as in a foliar spray twice a week. If you do this the problem should stop spreading and the plant will recover in 10 to 14 days. The stretch might have been stunted forever but different genetics and different phenotypes behave differently, so you'll just have to pray and wait . Hope this helps ! rocket: