This is gyp. It is 2000 lumens/40 watts = 50 lumens per watt. A Sylvania Sky White T8 fluorescent bulb is 2700 lumens/32 watts = 84 lumens per watt. Thus, their statement, "The LED tube included uses 30% less power to produce the same amount of light as fluorescent light bulbs." is a big fat lie. In fact, it uses 68% more power.

Hi aruzinsky.

The specs says draws 20Watt, it is only the size of a 40w T12 or 36Watt T8 I quess the leds will be around 18 watt (90% efficiency for the convertor) so around 2000/18 110lumen/watt a pretty common value for led tubes, but indeed the general info is not clear. But as always what will the poster? supplemetary or main light ? for his kind of (high light) plants I think it will be difficult to get enough light with only those tube lights as main light

My bad. And, I can't answer the OP's question.

Maybe this link has the right info ?

http://www.cactusinfo.net/artificial_light.htm