Hi,
No worries, the rockwool must be moist, not soaking wet, 600-650 ppm (at x500 scale) is where I would run it. If they are drooping, water your worst one and wait 1/2 an hour then look again, if it has perked up they need more water. if not it is probably a heat issue. I understand that you are running the lights on at night and cant keep checking them but you wont get roots down properly if you overwater. 8 year old seeds aint great but usually it would be a germination problem and obviously that isnt the case otherwise we wouldn't be here now. Buttttt. If you want to do this seriously get some good seeds off the internet, not from a mate. Indicas are better for beginners than sativas. diseases can spread through seed stock as well so who knows what you are growing really.

The tent, please find time to read my thread on pvc tents on page 1 of sick plants. Don't be stubborn and discount this as a problem as i have been growing for years without a major problem until this issue bit me on the ass, and it bit me big time. I lost all confidence in growing and almost gave up. now I'm back a little more wise and things are looking bigger and better than ever.

I believed you about what the bottle said but i would still email gt and find out why the labels vary between the uk and canada.

Talk soon,
Subzero.