Leaves took a turn for the worse.

Ok, here goes. I will try to include everything that may be of help, if I neglect something let me know, this is my first time growing and I am far from a green thumb. Until recently the plants looked great and all information to date has been obtained from this site, so thank you all.

To begin with, seeds were planted on July 15th and were under 24/7 light until roughly a week ago at which point I switched them to 18/6. Temperature inside the cabinet is usually right around 80 degrees. It hit 90 right before the pictures seen below were taken due to a fan burning out; this issue has since been fixed.

The issues with the leaves also just started when I transplanted about 2 weeks ago. The crunchy leaves at the bottom happened almost immediately, while the yellowing is recent. I figured the crunchy, shriveled leaves were due to transplant shock, I could be very wrong. I also thought I had purchased nice soil; though now through further reading realize I may be wrong again as it includes peat moss. They are currently in 8 inch pots and will be transferred to 12 inch pots before flowering.

Set up details:

Lights: 5 fluorescents and 4 cfls
Fertilizers used: started with miracle grow, switched to Fox Farm Grow Big after a few weeks. I will switch again to Fox Farm Big Bloom when flowering.
Soil: started with Hyponex, switched to Black Gold Organic when I transplanted 2 weeks ago. (soil includes: peat moss (I know), compost, earthworm castings, forest humis, perlite and pumice)

I added lime yesterday because my best guess was low Ph leading to nutrient lockout, though as I said, I only know what I have read here and it was my best guess. Any help you can offer would be greatly appreciated. Hopefully they can be saved and if so do you have any ideas on how much longer I should leave them in veg growth phase? Thank you in advance for your help.

You've gotta run out and get a pH test kit NOW and do a runoff test. That isn't good.
Also I am seeing that looks like pots with built-in drip trays? Rip those off and I'll bet it's wet under- tip the plants out of the pots and I'll bet the bottom couple inches are totally waterlogged.
You need excellent drainage growing a fast-growing plant like cannabis indoors, adn that type of pot doesn't provide it.

I have a Ph tester for my spa, I will see what it comes out to tonight. When I water them I tip them to let out the excess so that it is not sitting in standing water. I also use a water meter and it never says wet, just moist or dry. My larger pots do not have the same attached drip pan so maybe I will transplant when i get home tonight along with putting river rock in the bottom. Does it seem like it may be be low Ph locking out nutrients and if so will the lime I added last night bring it up?

Aside from checking the Ph, is there anything that can be done to help them along? Is the yellowing nitrogen or magnesium deficiency? Meaning should I spray the leaves, add epsom salts, etc.?

Find out your ph first....if it's off it doesn't matter what you do to it....fix the ph.

Not to be mean...but i've heard several people say the same thing as you did and I'm curious....why would you not test the ph before assuming it was low and why not test the ph of what you are adding....especially since you have access to some sort of ph tester.

Again...I apologize if I sound mean or rude; it's just that I've seen several people do that kind of thing and am curious as to why you'd approach it like that. :)

Not taken as rude at all. I am new to this and until recently was unaware of Ph and it's ability to cause so many problems. I previously (until about 1-2 weeks ago) had them planted in different soil and there were no problems at all. Once I transfered to the new soil the problems began. I then read a few posts about peat moss and it causing low Ph (i.e. it is at 4.5 or so) and thus figured that since I had no previous problems my water was fine, Ph wise, and related it to the peat moss. I found another post stating that lime will help bring Ph up to about 7, being very close to optimal range and figured I would add the lime, hence fixing the Ph. No testing needed. I am obviously wrong and will test the Ph when I get home today. If it is still low, which I assume it will be as it has only been one day I will try to fix things from there. I am just unsure of whether or not the lime will help fix this or if I need to lose the soil (Black Gold) and revert to another type of dirt, Fox Farm is not available near me. Then on top of it, if the soil balances out I am still at a loss as to what the issue is with the plants, hence unable to fix them. Thanks for the reply, I will keep you posted and any further information would be greatly appreciated.

I'm not a soil grower but Stinky will be back I'm sure to answer the soil qs.....phwise...yes, always check because there could be things in your water that react with certain soils etc...and send your ph in weird directions.....and it could be the opposite of what you think. Your ph could be high already (maybe your water has high ph or....?) and then lime on top of it.....now higher ph.....plant cannot take in nutrients at incorrect ph so that's why foliar feeding or adding more things won't help (and may even hurt) before you fix any ph issues.

Definitely makes sense. I don't think it is high already due to the peat moss only suitable to lowering it, but I will check it later today none-the-less. I figured I can check it then transplant them into the larger pots as Stinky mentioned the ones I have being no good anyway. Hopefully that will make sure I don't over water as I just watered them and will have to again to obtain the run off. So, if they are still standing when I see them next we will take it from there. I will await Stinky's input on the soil issues and post Ph tomorrow. Thanks for the help.

Even tipping the water out, there simply isn't the air flow you need to dry out the bottoms.
Low pH issues are compounded by extreme wetness.
River rock is unnecessary.
Repot, use a soil with plenty of perlite, and when you do, check to see how soggy it was in there! Trust me, my local grow buddy was using those too and almost lost her mothers- when she gave them to me for doctor services, they were sitting in an inch of water inside the pot.

Ok, so obviously lose the current soil (Black Gold) that I am using. Should I go back to Hyponex, with lots of Perlite. Is there anything wrong with that soil. I switched because I figured organic was better, but I have a bag I can go back to.