5th Week Veg--Dying Lower Leaves

Hello. 1st grow. This is my 5th week in veg of an Afghan kush in DWC. I have it in a 5 gallon bucket. The roots look great (there's a ton of them poking out everywhere), and as you can see by the pictures, the leaf growth is also nice. I have been doing Lucas formula of Advanced nutes jungle juice at 1/4-1/3 strength since week two (and I do a complete water change every week). The upper/newer growth looks great (aside from maybe being a little wrinkly-looking?), but just a few days ago I noticed the lower 4 leaves (the 3-point and 1st set of 5-point leaves) starting to form dark splotches that eventually turned into the brown dead spots and curling that you can see in the pics. This was also accompanied by a dark purpling of the stems of the 5-point leaves (You can also kind of see this purpling in the pics). Also, the main, middle vein leading up the leaf from the purple stem turned a little dark reddish, coming from the stem.

I have not been able to find any bugs with my 30x magnifying glass. My only guess is that this is a nute deficiency, and that the purpling/reddening is the plant eating up the lower leaves to supply new growth. When this first started happening, I upped the nutes to a little about 50 percent Lucas form. and added a teaspoon of Epsom salt (also I have been adding a teaspoon of H2O2 every weekly change since the beginning). But this seemed to make it worse and I saw what seemed like very early signs of nute burn--the roots even looked a little burned--so I changed the water out to pH adjusted plain water for a day before returning to the 1/3 strength without Epsom salt. The roots are white again, and the slight nute burn on the tips of the new growth is barely visible with a magnifying glass. However, the original purpling stems/dying lower leaf issue is still present.

More details: I am 1 day away from getting an electronic pH tester--I have been using a liquid drops/vial/color-coded pH testing system, but it only goes as low as 6. The 1/3 Lucas formula brings the pH down to just around 6 (I have tested this by slowly adding more and more nutes and repeatedly testing pH--watching it slowly lower to 6 pH). I'm guessing that perhaps 1/3 Lucas is not enough nutes now? but when I brought it up to 50 percent Lucas, perhaps that brought the pH too low and caused the nute burn? (I am also getting some pH up with my pH tester--I already have pH down).

What is happening to the lower leaves also seemed to occur in the first set of single point leaves before I started adding nutes and ceased once I starting feeding. That's another reason why I'm leading toward deficiency.

Even more details: Lighting: 150W daylight CFL with hood + 4 smaller lamps positioned at side angles, each with 23W daylight bulbs.
light schedule: 20 on/4 off
medium: clay pebbles
Bucket: black hydro bucket
air: 4.5 liters/min.
small clip fan blowing on plant from a couple feet away
room temp: 72-74 (have not yet tested dark time temp)
water temp: 72 F

Well that was detailed...let me know what you think...any help is greatly appreciated...thank you in advance

..................nobody?................

I've vegged plants under cfl's for over 2 months just fine, but lower leaves not getting much light will die off on a healthy plant.

The problem is probably the ph, even though 6 is ideal for hydro some genetics prefer slightly higher. I would try raising the ph to 6.5 and use an equal part formula instead of the lucas formula (it's listed as 'transition to bloom' on the bottle).

thanks guys! just got my tds and ph testers so I'll try upping the pH

ten characters walk into a bar

so if you are getting red streaks or red stem or red stems on fan leaves (hard to tell but looks like that might be it) plus slow growth, thats usually a later staged ph sign, if your leaf serrated edges are flared upward, that is usually a sign that your root zone is not optimal. I should say, this is based on my research, I am not a master grower. However, if you are getting multiple signs of deficiencies, that is definitely a later staged PH situation as well. I will say you can bring them back, it just takes time. I tend to turn the root zone around as quckly as possible, even though .1 change per two days is recommended. If you try and correct it quickly, depending on your strain, it could kill it or prove it a hearty plant. So just adjust your ph to correct zone, by measureing the run off water. get an electronic ph meter, you can get them on line for like 10 bucks. i dont recommend getting cheap soil meters, didnt do me good. anyways, good luck.

oh and as far as cfls and growing under them, i rocked 12 6500k 2800 lumen bulbs plus 12 26 watt 2700k 1750 lumen bulbs and was able to fem and top my plants into a scrog, 4ftx4ft. i would suggest using hps though to flower, youll avg closer to a gram per watt and you can use hps in veg, im doing it right now w results that are satisfactory at worst. Metal hallide obviously would be optimal bc of the light spectrum for veg.