one 400 12k question

[vainzane]

I looked but cant seem to put together an answer. i thought i had my light set-up right. i have a 55 gallon tank with a carpet nem and a couple of false clowns been doing well for some time. i started with t5 adding up to 156 watts i now have one mh 400 watt 12k. is that enough for a 40" long 20 inch deep tank.