I know we've kicked this topic around a bunch, and I understand that there isn't set it stone numbers. What I'm confused about, is why two of our stickied threads are wildly different:
http://www.plantedtank.net/forums/10-lighting/184368-lighting-aquarium-par-instead-watts.htmlPAR Values(Source) - Thanks Gnomecatcher for the suggestion!
Values between 10-30 are considered low light.
Values between 30-80 are considered medium light.
Values between 80-120 are considered high light.
Keep in mind that these values are what is currently accepted by the community as accurate, and aren't set in stone.
So I'm not looking to start a fight, just trying to understand if the numbers have just evolved over time and one thread is older, or what?I don't believe there is any consensus about the definition of low, medium and high light. But, here is my definiition, subject to, and almost certain to change:
Low light - 15-30 micromols of PAR - CO2 is not needed, but is helpful to the plants
Medium light - 35-50 micromols of PAR - CO2 may be needed to avoid too many nuisance algae problems
High light - more than 50 micromols of PAR - pressurized CO2 is essential to avoid major algae problems