Its not the "300 Watts" Einstein, its the HIGH INTENSITY DISCHARGE. Go put a t5 1-2inch from your canopy then put a HID 1-2inch from your canopy, tell me how that works out for you. Some people just seem to know everything when after all they know nothing at all.
Sorry, but I have to disagree. I have used HID lighting throughout the whole grow, from seed to harvest, with great success. It's how I started out when I had a small budget. T5's weren't even around and I didn't have the cash to buy other fluorescents, so I bought a 600 watt HPS and ran my cycles all the way through with the same light, I didn't even have a MH bulb for veg. As long as you keep a safe distance with the light, an HID light will grow cannabis just fine.
Not trying to beat you up, but I caution you to not call other people out and make smart remarks, when in fact, it is you who do not know exactly what you are talking about. Of course you can't put an HID 2" from the canopy, but I didn't hear anyone claiming to have done it, including the moron OP. WeedKillsBrainCells was only making the case that 2 150W HPS's
over 200 plants would most likely not cause the OP's problem. It's pure physics. The space needed to have 200 seedlings would require the light to be a considerable distance from the plants in order to make a footprint big enough to cover the entire area.
I believe the problem is his soil, he's using a cactus soil that is not suited to MJ. Myself and others have told the OP this, but he doesn't listen, claims to have years of experience, yet he does not know what kind of soil to use or how to take care of seedlings.
Again, not trying to start a fight, just some constructive criticism, you do what you want with it.
Peace,
GS