First Grow using a NFT system 400w MH and HPS lighting system

Hey hows it going
Recently bought a NFT setup
1800 x 1100x 600 cupboard.
Using seeds from a friend who uses them in soil .
Will post pics etc and keep u updated on how they are going ( not sure if this is the right section)
Would love to hear any suggestions and tips to help along the way
Already have a few questions.
- Been reading alot of nutrient charts and guides .
With regards to the first few weeks i want to keep the ppm around 200 -300?
- Using budzilla nutrients also have bloom not sure which is the best to use.

Day 1
Soaked Rockwell cubes for about 2 hours water of a ph of 5.5
Then planted the seeds into each Rockwell cube (8 in total).
Leaving them in a warm cupboard to germinate

Checked the water from the Rockwell cubes and it is reading 6.1 hope that wont affect it too much.

Thanks

Day 5
Just thought i update you guys. All the 8 seeds have germinated but none of them have sprouted( is this okay?)
Placed them under 400 mh light hoping they will sprout sometime soon.
Attached a picture of the grow set up
.
Also placed 4 more of my mates seeds and also 2 big bomb seeds ordered from attitude. ( i thought just incase the first lot of seeds dont sprout.
Keeping the temperture at 21- 25 degrees

Any suggestions would be great still got a bit of cash to spend
Thanks