Yes - you heard me right... :-) Or maybe I should rephrase my question - If I put the aquarium in the middle of the amazon river, and it's day, no clouds - I get some light intensity over the surface of my tank. Now how many Fluorescent Watts should I provide to get the same intensity? I know Lumens and Lux are not the right thing to use but still - I read somewhere that the sun is 30,000 lux. I think a good 36W T8 Fluorescent is ~2500 lumens. If I have a surface area of the tank of ~1.25 square meter. Then that's 2000 Lux per Fluorescent. So 30,000 / 2000 = 15 Fluorescents. Multiplied by 36W gives - 540W and divide it by 200 gallons = 2.7 wpg. Too low I believe - so this is why I am asking... Aviel. ------------------ To unsubscribe from this list, please send mail to majordomo@thekrib.com with "Unsubscribe aga-member" in the body of the message. Archives of this list can be found at http://lists.thekrib.com/aga-member/