Yellow and brown spotted leaves

Alright stoners and stonerettes, here's the problem. Theres these plants in a small cabinet grow box, Purple Haze x White Widow clones, and they have began to develop yellow/pale leaves and brown spots, some leaves are becoming crunchy, and dead.

An opinion of one of my colleagues suggest that this may be the result of the cabinet being too hot, due to a recent heat wave.

Can anyone help me diagnose and fix my delicious babies?

http://i144.photobucket.com/albums/r...d/DSCF1732.jpg

http://i144.photobucket.com/albums/r...d/DSCF1733.jpg

Experience Level: Novice (although working with very experienced)

Your Equipment:
.1) 30W Flourescent lights
.2) 6" or so from tops
.3) Bare bulp
.4) Consistent fresh air
.5) Exhaust fan, no circulation fan, exhaust fan does the work.
.6) 30W bulbs, (warm bulbs) in the Kelvin range, 12/12 cycle

Your medium:
.7) Planting cubes and Roton (clay balls)
.8) 6" planter
.9) Planting cubes used for clones

Your nutrients and water:
10) Tap water that's been left to room temp.
11) No pH. checker
12) No pH adjustments
13)
FloraBloom: 0-5-4
FloraMicro: 5-0-1
FloraGro: 2-1-6

Mixed in 3:2:1 ratio, 30 ml:20ml:10ml per/gallon of water

14) Watering and feeding is the same time here.
15) No additives
16) Stable pH
17) 6.5 pH
18) N/A

Your growroom:
19) Indoors
20) 4' x 4' x 6'
21) Lights on temp 75-85*, lights off ~70*
22) No insects

Your strain:
23) Purple Haze x White Widow ~60:40 Sativa/Indica
24) From clone
25) Not autoflowering

well let's see, you do or don't have an exhaust fan that works? how do you get consistant fresh air?

by planting cubes do you mean rockwool? did you pre-soak the hydroton and rockwool?

you say you don't know the pH and you can't check it, but you know it's a stable 6.5? which is it?

by the way, you want your pH for hydro to be between 5.3-5.8.

how many bubls do you have? that's a big space for fluros.


-shake

The exhaust fan that's on it circulates the whole box, sucks air through the door.

Theres 6-3' bulbs, and 4-2' bulbs going.

Rockwool sounds about right, didn't presoak either but it didn't seem to be a problem with other generations.

Lol, you caught me, I have no idea what the pH is, I was told you don't need to balance the pH if youre growing with hydro, again it didn't seem to effect previous plants. But I'll keep that in mind.

I've got a Brom Thymol Blue indicator here, I'll give you a reading.

pH is reading at 5.6

what is your water source?

-shake

City water, tap water.