Hey guys I have a 40 gal tank 18" high. I currently have T5NO dual output fixture with a 21W 6.700k bulb and a 21W colormax bulb. I am trying to gain some more light for my plants, and also aesthetics. I am looking at the Odyssea T5HO fixture but am I going in the right direction. Im not really looking to go the C02 system way, but I will continue to dose Flourish Excel. Will this light get me to the High end of low-Medium light? Will this much light promote a algae problem, and would I have to inject CO2? Thanks for your help.
I really like the Zoomed bulbs, they are inexpensive, readily available and have a good reputation. I ditched the "plant" bulbs long ago. I had ran a PAR meter under the light in the tank running and the PAR with the plant bulb was much less than it was using the combo of a 6500k and 10,000k which I feel gives a great coloring and plant growth.
here is a nifty chart that Hoppy has put together on various fixtures that gives you a good idea of where you are in the lighting scale.
http://www.plantedtank.net/forums/showthread.php?t=105774
I have an Aquasun fixture (not known for the greatest reflector) over my 40b suspended 4" over the tank. I am able to grow any plant I want to, but need to use co2 or algae becomes a major pain.
Of course since the 40b is such a wide tank I have a 26 Watt CFL pointed at each of the back corners to keep that area well lit.
Ignore any WPG comparisons, the WPG rule was for T-12 bulbs and is completely useless for more efficient forms of lighting such as T5ho.