SuperCritical Autoflower spots on leaves...Need help...

[brusake]

I'm growing GH SuperCritical Autoflower...I'm 3rd week vegging and some brown/rusty spots that looks like burns appeared in the middle of the leaves.I'm growing hydro ph is between 5.6-6.2 , temperature around 27C ,humidity 42% and I'm using 400w hps.
It's my first real grow so I don't have any experience on growing and I could really use some help diagnosing the problem...thank you

 

[namvet25]

Looks like starting of cal-mag def and phos def. Have you given them nutes yet?

 

[brusake]

Yes....I'm using General Hydroponics Flora series....I'm currently using 1/2 strength of what is written on the bottles since I'm not so experienced with nutes and didn't want to get any nute burn...
Should I go to full strength?

 

[faded187]

I don't use flora series but I would wait for someone who does cause I would never go full strength you can fix too little,but ur shit out of luck if u use to much.