[leonroy]

Going for a massive tank (well compared to my previous) and a bit confused as to which lighting to go for. The tank is 30" deep, 64" long and 25" wide.

Going by the Watts Per Gallon rule of 2-2.5W/gallon I'm looking at 380-475W.

That's a lot of wattage and I'd like to be as energy efficient as possible without compromising on light output and quality. Are LED good enough yet? Would T5 or MH be better?

 

[2in10]

3 X 80W T5HO separated by about 6" would be plenty of light for the tank. Just get good reflectors.

Watts per gallon are only good for T12 lights. Jury is still out on LED because the spectrum is so focused.

Also check out the sticky at the top of this forum by Hoppy to get some fantastic info and help.

 

[jcgd]

You want to shoot for par at the substrate, not watts/ gallon. Is there a canopy on the tank? You might be better using 2- 2 foot fixtures and 2- 3 foot fixtures for good spread and easier to find/ cheaper bulbs if you have a canopy to hide them in. The sticky on par levels can help you decide how many you think you need. Three rows will probably be fine. 40-50umol on the substrate will let you grow most anything.