Ph is fine at 5.8. The leaves could use some more green in them, in my opinion, so that's N.
Those burnt looking spots can be from low nitrogen; which I think they are.
They could also be light burn or maybe calcium deficiency, but I'm doubting that since you're adding it.
Not looking to argue with
@rkymtnman but a PPM of 600 in GH isn't overly high.
They changed their feedchart format so it's hard to link it but the "medium" feed for week 3 is 650-850 PPM(1.3-1.6EC) and week 4 is 800-1000(1.6-2.0). Heavy feed is 850-1050 week 3 and 1050 to 1250 week 4. I know lots of folks on here run the lowest dose that keeps the plant healthy, but GH usually runs a bit higher PPM/EC than most other brands I've used. You certainly can't use that kind of PPM with Jack's or you'd fry them.
Me I'd go up to 800-1000 PPM and see how they do. I don't see much tip burn so you'll notice in a day if it's too hot for them.
Again, me personally, I wouldn't pull any leaves off a small plant, especially if there's a chance she's deficient.
