I understand you completely, I used to feed my plants with the full dose for photos and I always wondered why the tips were burnt even though I gave them half the recommended dose. Every manufacturer has prominent feeding charts but i didn't know it at that time.Good luck bro and happy growing.
@Whitewizard, I tried to flush it for 2 weeks and now it seems to be "better". At least I learned that autos don't seem to require nearly as much nutrient as a non auto. Also, my local water is soft AF like I've never experienced elsewhere.