Too close ?

I have 10 plants 18 days old under a 400wt HID. They are at a distance around 3ft x 4ft apart.
The problem I have is that they are getting so dence @ 7 to 8 inches tall by 14 inches diameter ( tip to tip of the fan Leaves )
Can I use a 125wt CFL to produce more light to the lower leaves without causing any growth problems ?

yup. get a color different than your HID.

if u have hps then get blue CFLs.

The CFL I have is a Blue, I used it for Propagation. would that be ok ?