Brown spots!!! Female?!

What is goin on? Shes been doing this with all the older leaves for a while. I keep thinking it's MG def but I'll add Epsom salt and wont see a difference. I checked my ppm its fine, ph fine, no bugs, constant wind blowing, lights are 18 inches away (250W MH) and supplemental (68W CFL warm) I started 12/12 two days ago because I started seeing little blooms in between the branches but no signs of sex yet. Feminized seeds but I know still a chance for hermie or male. Does anyone know what the Spots are? the tips seem burnt and dead, I just started upping the nutes so idk if its nute burn.

Also can anyone tell if it's a girl or not?

This is a Violator Kush from Barneys Farm about a month old now.

if u just started nutes u must take it slow 1/4 ..1/2.. then full ****** to early to tell sex****** good luck

Thanks philmo, I'm only using about 1/2 strength right now, which I added 3 days ago. On my next reservoir change should I decrease the nutes even more or leave it at half? Or just use plain water for a few days?

dont look like nut burn looks like heat burn or not enough air flow

I have a fan blowing 24/7 but my a/c has been out and it's still warm here so that's a possibility, it doesn't feel super hot on the canopy though. could that be super damaging to it?