My entire 400 is very well lit with only a few T5s on (dusk/dawn). Still low heat... no shimmer though. You're dead-set on LED?

Probably 6 ft 210.

Yeah I like the idea of the LED's.

Cheers,
Vic

When are you getting a 210g Vic?????

Renos First :(

Cheers,
Vic

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.