Hi, assuming you're growing in Coco - you need to be feeding at every watering event. Coco does not hold any nutes and issues with cal/mag deficiencies will certainly show up if you're not feeding at every fertigation event. Check out the site 'Coco for Cannabis' - search for their watering articles. Wealth of quality info and always someone in the chatroom to help you out.
do every third for a bit. it'll clear up. that early the soil likely still has plenty, so becareful early on. the moment you see symptom, dial back, if you are going to try to feed as much as possible