Q & A: Lighting the Planted Aquarium
David R. from the UK writes,
"Hello if you could please i would like some advice, I am setting up two
tanks one cold one warm 7x2x2 cold 6x2x2 warm i want to plant my tank I
was thinking of using two T5 80watt tubes with reflector. Do you think think would be ok or would i need 4 80watts tubes on both tanks? Thanks"
I assume that the tank you are using for the planted ecosystem will be the 6' long tank. If that is the case, the volume will be around 179 gallons. At the very least, with a ratio of 2 watts/gallon, you would need about 358 total watts of lighting. If you plan on using four 80 watt T5 bulbs, you would be close. We typically recommend a ratio of 3 watts/gallon or higher, but some of the newer T5 lighting systems are very efficient in their design. Some companies incorporate individual reflectors per bulb that almost encase the bulb and preserve most of the bulb's intensity or lumen strength. Finally, it should be noted that the spectrum of the bulb is as important as it's wattage. Light in the 6500K range seems to work best. Good luck!
Joe Pineda is the Chief Technical Officer for Infinity Aquarium Design and is one of California's most respected professional aquarists specializing in marine science and biology and aquariums systems engineering.