1st off the veg stage does not start at a week , week and a 1/2...

soak your rockwool over nite...shake out good. place seed, and put in a small netpot filled with hydroton...spritz 5-6 shots-2-3 times a day to keep moisture around. place net pot in bubbler under fluoros...use plain water with a ph of 5.8. 5.5 is too low except for 2-3 weeks in flower.

that's it.

a plant is seedling until 4-5 alternating nodes. not counting the cotyledon... Never give nutrients to seedlings. Never! then just go with veg nutes once rootzone establishes itself outside of netpot, and you have 4-5 nodes on the stem...add your veg nutes. Goodluck.

In the future you would be better off if you just described the problem you are having, or ask a question. I didn't read your story! I read the long response you got, and had to correct that response.

Hydro is simple. Keep it simple and be patient! Or you will Kill another batch...

If you have not gotten a plant to live in 4-5 tries...might consider giving up. lol