Gunnar&Carey is spot on.
Lose the Mylar.
Flat white paint is slightly more reflective. but still, MORE reflective. I had some nasty refocusing of light that burned a couple of my ladies using the mylar. If you're doing a room-within-a-room, try Orca film, or Panda film. Black on one side, white on the other. Works great!
About your lighting,
That one big ol' T8 monster you have there is PLENTY for those li''l pups. Hang it so the bulbs are like 4 inches away from the tops of the plants. Get some of those ratcheting light hangers and raise the light when the plants get taller. at one month old they'll be mature enough to bud up. with Bag seed though you're likely looking at Hermaphrodite seeds. Read up on sexing your plants.
and WATCH CAREFULLY FOR MALES!! they are evil. and should be killed.
Lastly.... those pots are a little on the huge side for such little beasties. but they're in, so leave 'em. aim to water and feed right at the base of the plant.
With FF Ocean Grow be careful NOT to over feed. Ocean Grow is SO delicious out of the bag, it;'s easy to lock up the Nitrogen by adding more nutes. Feed lightly maybe once a week till they're a bit beefier. But if you do it right you can call your homegrow "O.G. Holeinthewall"
Keep going, keep us posted.
Remember... It will grow without you messing with it too much because after all, it IS a WEED.
peace,
MW