Leaf Curling and Mysterious Brownish Spots.. Who Can Be My Savior?

What Strain is it? Mk Ultra and OG kush #18(og is the taller plant, the one on the right)
Is it Indica, Sativa or Hybrid? What percentages? .....
How Many Plants? 2
Is it in Vegetative or Flowering Stage? Flowering
If in Vegetative Stage... How Long? both vegged about a month
Indoor or Outdoor? Indoor
Soil or Hydro? Soil
If Soil... What is in your Mix? ROOTs organics
If Soil... What Size Pot? 6.5quarts or 1.625 Gallon
Size (Wattage) of Light? How Many? 1 150w HPS, 1 125w CFL
Is it Air Cooled? NO
Temperature of Room/Cabinet? 90 peak, about 72 trough
RH of Room/Cabinet? 40%
PH of Medium or Reservoir? 6.8
Any Pests? Not that I'm aware of
How Often are you Watering? every 3 days
Type and Strength of Fertilizers used? FF Grow Big and purchased, but have not used yet, FF Big Bloom
Size or Square Footage of Room? 1.5'x3'





About two weeks before flowering my leaf tips started to point downward and curl under. Then the entire leaf would cup downward. Then i started seeing brown spots as shown in the attatched pictures. As you can see, the tips aren't the spot of initial burning but as the spots grow, the tips of the leaves become crispy and die.

I initially thought that i was over fertalizing, but i haven't watered with anything but clear water (pH of 6.5, ppm of ~180) for about two weeks now, and the new growth leaves are still cupping and curling, in addition to the spots getting bigger/worse. Also, i flushed both plants excessively about one week ago. WHAT THE HELLLLLLLL is going on!!???

This is only my second grow, my first was with miracle grow and worked out beautifully but tasted a little shitty. Now i'm running into problems like crazy.

The Og Kush plant doesn't really have any spots like Mk Ultra. OG has more of the curling/cupping symptoms while Mk has the burns. Today is the first day of week 3 of 12/12. I want to remedy this bullshit before it's too late.

i need help!!! I'm a fiend for knowledge and cannot seem to figure this one out! Please anyone!!

whats the temperature of the room

looks like your lackin some kind of nutrient guessin it would be a good idea to flush your plants with ph'd 6.5 - 6.9 water then introduce flowering nutes i would suggest somekind of supliment like cal-mag and supermax B1 with your flowering program looks like phosfurus def are they crispy to the touch

They look hungry. You don't seem to be following the official FF feeding schedule, which might be why you're getting deficiencies now.

See here: http://www.foxfarmfertilizer.com/FoxFarm-Soil-Schedule.pdf

Only some are crispy at the tips. The ones that have the brown rectangle burns in the flesh of the leaf are still healthy feeling and respond to waterings like other healthy green leaves. I was thinking cal-mag because it seems to be everyone's solution to non-npk nute problems. thanks for the advice man, a trip to the hydro store awaits me.