10lbs? Lol, make sure you dont freeze them babies! ;] And you dont really need that much of co2 for such young plants, yeast co2 generator would suffice.
Those look good, definitely better than mine did at this age.
As for the co2 Im not sure you should add any at all in this stage unless this closet has no air exchange whatsoever which I doubt. And I suggest you read up on it first, too much co2 can do more damage than not enough and with just a big slab of dry ice i can imagine you add a lot of it with no means of controlling it.
Thanks ekim, it wasn't all of them but I could see roots on a couple of them. Can I flower with the same light? I know HPS is better, but can I do it with my MH light?
A couple of things, you can flower with a MH I have a friend who just won't buy a HPS, and he still gets good bud, but you will get better results from a HPS. You mentioned your rez temp at 72, try and get that down to near 60 if you can, you'll get a much better O2 exchange in the roots, and hi rez temps leads to root slime.
Thanks Watts, I will work on that. Can i just use frozen water bottles to bring down temp? Also I notice a few of my plants stem and some branches are turning purple and some of them stayed green. Is this a concern or just genetics?