Is this burn or deficiency?

Hello everyone
Having a little issue with these purple kush ladies.
Not sure if they are getting burnt or a deficiency.
Growing method: RDWC- 26liter totes buckets
pH: 5.8 on water changes and climbs up to 6.2 to6.3 when doing a weekly water change.
ppm:600 with RO starting at 60ppm
1000watt hps
Temps 27C
Humdity 70%

If there's anymore info needed to help out on diagnosing these ladies I will reply as quick as possible

Thanks for reading my post.

burn, i wouldnt change it up though

Week 4 into flower

i agree with hexthat it is a little burn on tips that on edge of leaves is heat ,but it looks good i wouldn't change any thing,over all nice looking garden

I am also using a sulfur burner

Here are some update photos at end of week 5
How come the top buds are small and fluffy compared to the lower ones?