Yellow leaf, and brown stains

[Tautvis2020]

. Hey , i m new to breeding.

I have problems

1. Yellow leaf and brown stains

2. White stains onto green leaf

3. Why occurs leaf branch?

My kids 3 week.
Lights 600
ETC 0.9
ph 5.8

day : 26-28 temp
70 - 75 %
night 20 22
80 - 85 %

 

[Rwise]

1. PH/root issues
2. Bugs, leaf miners
3. I am not sure what you are asking, pics under natural light will help, I cant see the true colours.
Read this page https://www.growweedeasy.com/cannabis-symptoms-pictures