Problems from soil to hydro

Ok so here's my first real hydro grow and I'm having problems diagnosing my leaf discolorations. Ok so heres my setup:

Auto Flowering Hindu Kush

Top feed drip system w/ 3g pots

600w HPS

Botonicare PRO series along with silica blast and sweet

Plants are about 5 weeks old, 12" tall

Ok, here's the problem. A few days before sexing I noticed the lower leaves started discoloring at the tips. Ok thought it was nute burn so I flushed with Flora Clean for 2 days and restarted feeding. Now 2 weeks later the bottom 3 sets of fan leaves are completely yellow with most of the curling up with brown tips and dieing off.

Thought maybe it was a N def so I kicked up the feeding a couple days ago. Still no good news. Only using about 1/2 the rec amount for feeding right now.

Lower leafs start to turn yellow and then brown at the tips.

Yellowing and browning moves up the plant.

Leave stems are turning red.

Stunted growth of flowers.

Ive even noticed some necrosis in a few of the fan leaves.

PLEASE HELP before I loose my 14 babies.

bump it up

when your plants are yellowing bottom up it can be a # of things.. In order.

1. PH problem, this is usually the issue.. Check your PH and stabilize it.. If your PH is off your plants are being choked out.
2. Make sure no light is hitting the water, algae will grow and choke em out.
3. Feeding, be careful with this one. Done over feed them to counter an issue. Check your PH, make sure you're using good water (not tap right out of the tap), RO is recommended.

Once you have HYDRO down its easy cheesy japaneesy...

1 word of advice for your new hydro setup... Be vigilant in your care, dont slack off for a week here and there and keep it all CLEAN..

~cheers

ps..

if you are using RO water make sure to add CALMAG (calcium and magnesium)