PAR levels?

[delfisherman]

Im a electrician by trade and deal with leds all the time with work and i have noticed that everyone keeps bringing up par levels in planted and reef tanks. i have never used par levels in any measurement of light qnd it makes no sense. light is measured by lumens so why wouldnt you just use a high lumen light to get just like the old wpg rule. I have a snake eye high lumen light from aquatraders over my 29 and its high light. Par just seems like a fancy way to make more money with this new supposed measurement

 

[mr_X]

You would not be best served measuring light with lumens because photosynthetic creatures use only certain wavelengths, and the others, though they may be bright, are unnecessary.
What you want is a fixture that puts out enough active, or usable energy. It's not a way to make money.

The watts per gallon rule is found to be useless as well, since water depth and the amount of photosynthetic light coming out of the fixture are major factors, as are the light needs of each individual coral or plant you intend to keep.