Anyone using Par 38 LED's on their tanks?

[imisky]

4x PAR38s (any brand) will not light a 6ft tank efficiently. With 80degree optics they will produce enough PAR equivalent to 250W in the middle of the 1.5' x 1.5' coverage and falls off. This is enough for LPS, but if you add in SPS then the range shrinks down to about 1' per bulb.

LEDs are the way to go. PAR38/DIY/ or commercial units as long as its spec-ed out for the system it'll work well.