Leaf Septoria?

[Jonbones]

Hey guys new here on the forum been lurking around now for about month and now im in need of some advice if anyone can chime in.

 

My white widow x big bud are looking a bit on the unhealthy side, to me it looks like leaf septoria but im unsure?? A bit of history, in there 1st week of veg we had some cold nights, I noticed droopy leaves some purpleing on the edges and dark spots on the leaves so i got a heater quick smart. About a week on with constant temps sitting at 25-27 C the spots are still appearing and seem to be getting worse.

 

If any experts can point me in the right direction it would much appreciated.

Cheers everyone!

 

Indoor/Outdoor: Indoor
Growing Medium: Coco perlite
Growing Style: Hand watering/feeding
Watering/Feeding Frequency: Weekly/or when dry. When i repotted the seedlings i overwatered so im guessing cold+overwater = disease??
Nutrient Strength (PPM/EC): Got there 1st feeding 2days ago. A+B, with nitroboost and a root enhancer.
PH Levels: Fed at 5.5
Temperature/Humidity Levels: 25-27 C constant. Approx 20% RH too low??
Air Flow/Fans etc.: Oscillating fan on low + exhaust
Lighting Type (CFL/HPS/MH etc.): x1 600watt GalaxyHydro LED
Total Wattage:
Growth Stage:2nd week of veg
Plants Age:
Cannabis Strain: White Widow x Big Bud