1st grow have a problem please help Pics posted

So,

hydro set up 1 plant doing well and today noticed the brown spot on one leave???


Using CFL for Veg plenty of wattage

Seni grow A&B at about 600ppm

Plant from seed Unknown strain

Germinated about 21/2 weeks ago

18 hours of light

feeding 3 times a day

Have tons of air flow, heat at an average of 85 humidity at 35 to 47%


Please help


Thanks!!!!!

eek ive seen that beforee it could be a few things but whats happend to me is its like micro germs from the water eating ur chlrophill are you dumping h2o2 in ur water?

I've never done hydro but I would think that its nute burn because your feeding three time a DAY.

No h202 water Ph is at 5.8 using Distilled water from a bottle

aeroponic or??!!

Yes Aeroponic

how long you feeding it !!? 1 hr, 2 hrs, 1/2 hr??

I think it is about 1 hour