When you put your plant into the flowering stage it will show its sex either a male (with pollen balls) or a female (with a few whitish hairs). I would suggest looking up pictures so you can tell as soon as possible. You don't want the males to release pollen and cause your buds to produce seeds.
^ I agree with keefbox420. Use regular PH balanced tap water, water them once every 2-3 days or when the top of the coco is dry. very dry. I use coco grow medium right now and I usually water my babies when the top inch or so is dry.
It looks like your over watering them, with nutrients.
Last week I started germinating 10 seeds. 9 took to root, and one didnt do shit. I have 9 planted in COCO Grow Medium in separate oval cups.
I whipped up a small grow box while my larger "cabinet" is being built. I am currently using 2 24W CFL's for the seedling stage.
My temperature has been a...