"xtr396472" wrote in message
...
This is a good example of lighting requirements
http://faq.thekrib.com/plant-lighting.html
Takes your tanks measurements and multiple by plant requirements then divide
by 11 hours gives watts per hour. Measurements in inches

Hmmm... That seems to be a somewhat dubious formula. Working this
for my 6' x 2' x 2' (approx. 150gal tank):

Surface area = 24" x 72" = 1728
Distance of light source to gravel = 33"
Watt hours = 1728 x 33 x 0.18 = 10264 (for moderate to bright light plants)

Total watts = 10264 / 11 = 933W (!!!)

So, 933W for a 150gal tank, or approx 6W per gallon.

We are out by about a factor of 2 here, which is serious.

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com