Comparing Watts to Lumens

[that Reef Guy]

I want to get an LED Light for my 10 Gallon Aquarium.

Problem is they do not measure LED in Watts like they do for T5HO or Metal Halide so I am unsure how powerful they are.

How do you comapare Watts to Lumens.

http://www.fosterandsmithaquatics.co...m?pcatid=22443

This Marineland LED system is 1305 Lumens (What does that mean in terms of Watts).

Would that work out for my 10 Gallon Reef Tank (It is only 10 Inches deep with the sand). I am most worried about the Plate Coral on the very bottom of the Tank.

Since the Tank is so shallow could I get away with one of their cheaper models (I am not sure how LED will work out as I have not used them before so I do not know if I will like it or not and do not want to spend alot of money for something that I am trying out).

Marineland Single Bright $42.49 300 Lumens
Marineland Double Bright $79.99 450 Lumens
Marineland Reef Capable $179.99 1305 Lumens

Has anyone tried the Marineland LED systems before? If so what did you think of them?

Thanks in advance

[CalmSeasQuest]

Watts is a measurement of electricity (Watts = Volts X Amps)
Lumen (Luminous Flux, often referred to as LUX) is a measurement of light visible to the human eye.

While Lumen can give you a sense of how "bright" the light appears, it's a poor measurement for Coral. The best measurement for Reef use is PAR (Photosynthetic Active Radiation.) This is the amount of light falling within roughly 400nm~700nm which is used by corals for photosynthesis.

Light can appear very bright, yet not support coral growth (or worse, promote algae growth) based on the spectrum. The opposite is also true - LEDs generate tons of light within the PAR spectrum. While the LED light output may appear "less bright", it contains much more PAR and better supports coral growth. Many new to LEDs initially bleach their tank as they significantly underestimated the amount of PAR being produced.

The bottom line is neither Watts not Lumen is a good measurement of the effectiveness of Reef lighting. Try to find PAR values.

[pjr]

+1.... what he said!