We apologize for not answering your question promptly. For the Archaea Slim Pros, we consider them medium high light for smaller tanks up to 10 gallons. For 20 gallons we consider them medium light.
For the new Archaea Ultra Grow LED, we consider them high light for tank with width (front to back) of about 13 inches with a single fixture. For larger tanks, it depends on the width of the tank(the distance from front to back) for aquariums wider than 18 inches, we recommend 2 light fixtures to get really high light out put.
For PAR value, we do not really have PAR value for our lighting since we do not emphasize PAR value. PAR value is a rough guide, it measures everything between 400nm and 700nm. In this range there are also yellow and green spectrums which are not utilized by plants much for photosynthesis. As we know, the blue and the red parts of the spectrum are what is really utilized heavily by plants for photosynthesis. It is possible to have two light sources that have the same measurements of PAR value but different spectrum distribution. For example, source A could have higher value in the yellow -orang-green but lower value in red and blue and look bright to the human eye but maybe insufficient for plants to photosynthesize. Source B could have lower value in the yellow-orange-green spectrum but higher value in blue and red spectrum which does not look so bright to the human eye but plants can photosynthesize effectively.
In conclusion, PAR value does not necessarily tell you if a light is a good source to grow plants.
For our new Archaea Ultra grow LED, we do offer a spectrum graph on the package and on our website that clearly shows the spike in the red and blue spectrum for effective photosynthesis.
Hope these informations help!
Aqua Forest Aquarium