waterHi brother, when you see the pistils on the buds turn red ,its about 21 days from harvest remember its about 21 days! you need to look at the thricomes.. your plant seemed to veg for a little longer so it might take you another 3/4 weeks before harvest. I see you are using hydroponics and thats very usefull, you will flush about 3/4 days max before harvest because you will cut your plants right off the nutrients when you put them into RO or Tap water that waited 48 hours before watering ( i think its best to wait 48 hours before waterign with tap water). You got some really big plant and really big buds coming my friend! wish you the best of luck and happy growing! text me a private message if you got any questions at all about growing etc! :D