150 DE Lighting options (10, 20, 14.5, 13??)

[fkshiu]

This article may answer some of your questions:

http://www.advancedaquarist.com/issu...004/review.htm

No CCT data means just that: he simply wasn't able to properly/accurately measure the colour temperature from the lamp for whatever reason.

The reason why PAR goes down as K-temp goes up is because most photosynthetic activity occurs around 6500K. As a result, you can't have you cake and eat it too with high K and high PAR, generally speaking. That's why people use actinic supplementation. There are a few exceptions like the Iwasaki 13K 175W bulb on an electronic ballast that has more PAR than many 250W bulbs.