400MH distance to seedlings

So everything I've read about seedlings and HID lights says 3+ feet away. I'm running 400W Hortilux Blue MH bulbs with a initial lumens at 32,000 in a Cool Sun 6" air cooled reflector. Cervantes book says 4,000 lux max for seedlings/clones

How close should they be to the seedlings?

Total newbie question I know...just need a solid answer or help in figuring out the answer. Thanks guys!

seeing as they'll grow in full sunlight just fine you can get the light as close as a foot as long as you get all your plants in the lights footprint.

So as long as heat isn't an issue (burning the plants) then they can't get like "lumen overload" or something? I know the sun produces a lot more light than HIDs but the plants also don't spend 18 hours in direct sunlight.

Want a solid answer, put your light to closes to your seedling. Feel the heat, raise it higher until u don't feel that much of heat, if it warm move raise it a little higher, since u got a cooling system, there wont be any problems.
Your temps should stay around 22-27 i think. 25 was the preferred heat or something. I reckon 27celcius is fine, but may be warm.

I put mine about a foot and 1/2 awy or so with an air cooled reflector you could probably get even closer. I wouldn't worry bout giving them too much light just the temps. (Technically I use cfls for the newly sprouted seeds step up to my 250 for a little and thn go to the 400 but mainly just to conserve electricity a little)

Never have I ever had a problem with too much light.

Unless you count seriously depleted plants because they grow so fast, you can't keep the root system fed enough.

Thanks for the info guys!