If you're now adding a calmag supplement then give it chance to work, your new growth looks ok n doesn't seem to have any calmag symptoms, remember to water until run off in coco about 20%, also water everyday in coco for best results
I'm 90% sure it is calmag deficiency, up your ph to 6.2 and give it a few days see how she goes, 800ppm = 0.8ec ??
If so that's a little low, maybe up it to 1.2/1200ppm see how they go