I have a small cab of about 2.5 by 1.5 by3 ft and I need to know what is enough light for this small cab, I don't wan't to have too much light. And if i have Fluorescent lights what combination should they be (cool, warm) light.
IMO There certainly is such thing as too much light. The sun gives about 50 000 lumens per square meter on a clear summer day. The idea of an indoor grow is replicate as closely as possible the conditions your plants would be in outside on a clear summer day, which is the best condition for growing. To use more light than that can even harm your plants, can make the temperature very hard to control in mids 70s 'green range'.
A lot of the problem is heat. A small space with a large light needs to be vented. The way I learned was an unvented light needs about 1.5-2 feet over the plants. In reality I had larger problems with heat and non-existent humidity.
Once I vented the light... cha-ching! No more problems.
Now I have raised seedlings under a vented 1000w no prob but I move the light all the way up. I agree there is no reason to mega-radiate your little babies. Later, when there is denser foliage and light penetrates less it's appropriate to move it down as long as you've taken care of the heat issues.
IMO a 1000 watter in a 4'x4' space is still too much light..a 600 watt or 400 watt should do just fine with proper ventiliation..relfective surfaces can help your light like you wouldn't believe. Mylar is the best, definatly get some if you have a couple extra bucks.