Re: MH Bulb selection (Which Color Temp is correct?) by James Purchase
I've had a 770 liter (~200 gal) FW set up for about 4 months now with 2 x 150W MH.
Lamp pendants are suspended about 20 cm above the water surface.
These lamps are manufactured by Arkadia (British, I think), and are 6500K
lamps (intended for marine use, can't remember the CRI but is above 90 I think.)
*Very* nice fish coloring from using these lamps, a beautiful tank.
Plant growth is not enormous, but 30-50% better than a similar tank I have using 8 x 30W FL.
I think it would be better with CO2 injection.
Hence my recommendation: Use at least the 5300K lamps. 2 should be enough even for a 6 ft.
tank if the reflectors are good.
BTW: What does your tank look like? 120 gal and 6 ft length, is it 2 m (6 ft) by 0.45 m by 0.45 m.?