400w MH no pics yet

Okay so I was wondering if it was ok to use a 400w MH on seedlings, they are a few days old and seem to be loving it, but I don't have any flouros and it is about 20 inches away from the plant, is that ok? should it be closer or further away?

feel for heat when the lamp is on, the top of your plants should be where it stops feeling hot, further for seedlings
I use 2 400 watt MH all the way through too harvest
works great