Looking to get everyones opinion on this.... Is 400w adequate or should I push up to 600w. This is only going to be a 2 plant scrog DWC set up
If it were me I would go with 2 of these http://www.mars-hydro.com/mars-ii-led-grow-light-4... or 2x 250w HPS I don't think a single lamp system will give the best illumination in a 2x4 area.
I have a 2x4x5 tent. I started out originally with just a 400 mh/hps that was terrible. I moved to a 600. Better but the ends were terrible. I ended up adding a 400 watt led exactly like brother urb posted. The problem is a single light doesn't have the foot print needed to cover a 2x4. The buds on the first foot or so of each end were airy and fluffy from lack of light. I'm changing up everything right now adding more space, but having to start all over again with just a 2x4 tent I would go with two 400 (maybe 250) watt dimmable ballast cool hoods/ tubes. I prefer hoods but there's a single cool tube on ebay that held 2 bulbs i had my eye on. Add on one bad ass ventilation set up. Put some thought and serious planning into ventilation. So I guess to answer your question neither light would cover it by themselves in my opinion. I would go smaller double light set up
You'd be better off with a Metal Halide, 400 to 600, during veg then switching to HPS for flowering. Just using HPS alone will cause stretching. I use LED's also but only as side lights. I'm still not convinced they are good for a full grow unless you really saturate it. Add some LED side lighting and use a MH for vegetation and you'll be good to go.
Those rectangle shapes are hard to cover with 1 light, its what I faced with my 600w. I'd recommend a adjusta-wing style reflector and a 600w, they seem to be awesome for dialing in your footprint. That is, if you don't want to dive into LED, Brother Urb had a great suggestion.
He's using a 2x4 the light I just made covers that. He should make a light than buying Mars those diodes are inferior with poor penetration View attachment 1855494