We r on a roll finally , but need advice QUICK

We finally got everything up and running and have 4 10 gallon rubbermaid kits going, we got our 400 watt mh// hps light today and just getting ready to put seeds in to sprout, but needed to know how far to keep the mh light away from the system so it will not harm them to start them out as we only have the 400 watt mh // hps light system at this time...

Thanks.

Jamie

Thats a waste of $ (for the electricity), buy a 18" floruo or a CFL for seedlings, if you are set on the 400 watt for them keep it 3 or 4 feet away. They will let you know if its too close.