Twisted brittle leaves Shes going Fast HELP! Humidity problems??

Hello everyone! First timer poster here. Been through a couple harvests in DWC with no problems and I want to say thank you! to everybody here on RIU for being such an awesome community of helpful gardeners!!! I recently moved into a 4'Hx4'Lx2'W cabinet with two chambers to keep it a little more stealthy. there is 8-23w CFLs in there right now. I started an awesome indica bagseed about 4 weeks ago and she(hopefully) has been growing like a monster! Within the last couple days the leaves have been getting noticeably drier, darker, and extremely brittle. The color started to turn on the leaf tips and edges and now affects whole leaves. I changed the nutes and went with 1/2 strength i was running before. I just broke my ph meter so for right now im using the dumb strips until the new one arrives but my Ph is hovering around 5.6-6.3. The temps are a little high at 82 but there is good ventilation and there has not been any problems until now. Where i think the problem lies is the humidity. Its been at a steady whopping 16%!! Its been like this the whole time though and the fan leaves only started drying out about 4-5 days ago. Is it heat stress, humidity, nute lock out or what???! There is also a sativa clone in there that just rooted and its not affected at all by the humidity.

ANY help is greatly appreciated!!!

The first picture is of the new clone.

Humidity is -way- too low.

Crash course:

80-95% RH for clones, 60-70% RH for veg, and 40-50% RH for bloom .. as an average, some strains will like it a bit lower, or higher.. but your humidity (or lack thereof) will be the end of your plants if you don't fix it very quickly.

Ok so i went out and bought a small humidifier. With my ventilation on during the day the humidity stays at 16% but last night without the vent the humidity crept to 57%. will the overnight humidity blast be enough? Or should i go out and buy a bigger humidifier

Could be pump or timer failure.

This isn't a humidity problem this is an out- an- out burn. By the looks of it it is suffering multiple nute overdose, wow, look at at that.
Did you bump up your regularity on your controller? mix your res incorrectly? better start there. I KEEP my rooms quite arid, I do this on purpose. MJ will "thrive" in VERY arid conditions, and in the northwest where it is super humid you can controll fungus and mildew by not "CREATING" an enviroment for which is thrives. All this about it being "The end of your plants" is "horseshit frankly" A dry enviroment is not going to kill your plants. You will wan't to keep your clones in a humid enviroment while in process, but that is for another purpose all together. 20% rh and still trying to get it a little lower. watering less frequently seems to pull it down slowly.