Leaf discolouration ID - Cal deficiency or disease?

Thanks hashy but I don't think that it's down to nitrogen toxicity. Perhaps you were checking my other grow. I'm using Bio Tabs for this one, Black Cream Auto, they are slow release tablets that you put into the soil after 2 weeks. The only additional nitrogen I added was some dilute Biobizz Fishmix in the early weeks. No extra N in the last ~3 weeks or so. I am leaning towards calcium deficiency after doing a bit more research but hopefully someone else can chime in before I give emergency calmag watering. Sincere thanks again for your input hashy, your grows are amazing.

I have had a look at your feeding schedule from a diary of yours, I think it's from the one with this plant in. Looks to me like your giving quite high levels of nitrogen. This could be causing issues with the plant receiving other nutrients. You may be better off going with a bloom feed as your in flower.