imho, it almost looks like there is too much K which is causing an N toxicity and then like you're watering just a bit too often. definitely go to water only and let her dry out a bit in between. also, you are keeping your 400W about 24" away from the canopy and you could probably get it a few inches closer--lower it a bit and see how that goes; i think my 400 is about 18" from the canopy.