One Way to Design a Planted Tank LED Light

[m00se]

I just tested it in Google Docs and it works. Make a new spreadsheet in GD and then go to File/Import and choose "New Spreadsheet" and point it to the xls file. It will upload it then you'll be good.

HTH

[Wasserpest]

Is there a direct relationship between Lumen and PAR? I am not an expert, but I thought they are two different units, and things like spectrum play a role? Like having two LEDs with the same luminous flow, one with peaks in the yellow/green area, another one more in the red/blue photosynthetically speaking more significant area ?

[mistergreen]

Originally Posted by Wasserpest

Is there a direct relationship between Lumen and PAR? I am not an expert, but I thought they are two different units, and things like spectrum play a role? Like having two LEDs with the same luminous flow, one with peaks in the yellow/green area, another one more in the red/blue photosynthetically speaking more significant area ?

Yes on all the questions. On Apogee's site there is a lumens to par conversion equation. There is a relationship but it's an approximation for white sun light. A par sensor will have a peak toward the blue.