ive got a 6 lamp reflector 750mm x 1200mm and plan to build a grow box 1.2 sq mtrs x1.3 mtrs high would 650 watts of veg light be enough for that area and how many plants would it hold also how would 650w of cfls compare to a 400w hps.
First of all, comparing a watt's worth of CFL vs a watt's worth of HPS is comparing apples and oranges. Fluorescents deliver low intensity light; HPS delivers high intensity. It is the intensity of light which drives photosynthesis.
Luminous intensity aka brightness (measured in lumens or lumens per sq metre aka 'lux') from multiple light sources does not 'add.' Putting a dim lamp next to another dim lamp makes neither lamp brighter.
Since the lumen figure is a measure of brightness, a pair of 1500 lumen CFLs covering the same area is not applying 3000 lumens, rather 1500. It could be 10,000 x 1500lm CFLs and it would still be 1500lm. None of the lamps gets brighter by virtue of being next to one another.
While it's less of an issue, HPS is also much more efficient in lumens per watt than CFL- a bit immaterial as there's no such thing as a CFL that is comparable to an HPS in luminous output.
Plants flowered with fluoros will deliver fluffy, thin buds. Plants vegged with them will grow quite slowly compared to those grown with HID light. Fluoros are great for clones and seedlings, which don't need to be pounded with light.
You're a lot smarter to jump on the forum
first and ask what you should use instead of buying a bunch of stuff and later asking if it will work.
See about getting your money back for your huge batch of of CFLs.
Your planned grow box dimensions are going to give you grief. You'll need to make it a good bit taller than 1300mm, closer to 2m is more functional. Even if you grow SoG style, flowering clones right after they set root, which keeps plants rather short, they will be about 1m tall by the end of flowering with a 400HPS.
For 1.2m^2, you could use a 600HPS and could flower about 12-13 SoG pruned plants. You could also use a 400 and flower 8-10 in the same style. Either a 400 or 600HPS would kick the pants off anything you can do with CFLs- and considering you were OK with 650W, are both within your scope for power consumption.
