Need help With 1st Grow Ultra Newb

I have learned so much from everybody but I can't figure out whats going on. Didn't pH the grow mediums at first but it has been fixed. I spent a long time building this grow cabinet.. oh hell I'll just give you the specs with pictures to see if you can figure it out.

Temperature- 75 - 85 F usually 80
Humidity- 35%-55%
Light- currently just 24 Watt Daylight Flourescent
Plugs- Rapid Rooter
Medium- 1 with only Perilite and 1 with Perilite mixed with Vermiculite (both hempy style)
Light Time- 24 hrs/day
Strain- Barney's Red Dragon Feminized
pH- 5.8-6.0 (currently) 7.8 at the begining of last week

Only have pics from today. Ok see the the brown leafs. It started on the first ones and each one after. It starts at the tip then the edges and then the rest of it. No yellowing just green then brown. (Sorry about the pics being sideways)

get them into some good soil ..theres no need to have all that perlight on top like that mix your soil with perilight 50/50....then water them ..water only when the top 2-3 inches of soil are dry...feed them a light nute mix 1/4 of what the box says too start then work your way up from there..you might want to invest in a mh/hps light.growing 4 plants a 400w will work..i like to keep temps 70-75 daytime..65-60 nightime...humidity @55-60 is good...i almost forgot ph in soil 6.8/7.0...never higher than 7.0....

Trying to do full hempy with hydro no soil. pH of 5.8 with hydro I thought. Actually have the 400 mh/hps already just letting the roots reach the resivore before I move them to the larger chamber. I only water when the cups feel light and have fed them 1/4 strength nutes twice.