OG Kush #18- DNA genetics (reserva p.)

Some leaves got burnt but everything is good, just flipped to 12/12. I think the pH down is causing the leaves to burn or maybe my pH pen is not working properly (I've already calibrated it) so I'll stop adjusting pH, in the next couple of days there should be some pistils. I wanted to let them grow for around 9 weeks but I think they'll grow too tall for my tent. Forgot to add that I kinda supercropped one of them because I didn't want to defoliate anymore.