the tubes here we called PL is the same as your power compact in state. your tube is 6700K, the unit K is Kelvin which is the unit for temperature and in this case you are talking about color temperature of the tube. Where sepectrum is talking about the light wave emitted by the tube and that is different than the color temperature. you may search for your power compact tube manufacturer for the sepectrum spec. and if you found that please tell me as I also want to know. but I've heard that PL has the wavelength that promote aglae growth. For best growth of water plants the wavelength of the light should have higher power at 430nm, 555nm and 630nm.
you may refer to the following link,
http://www.nelsonlamps.com.au/products%20page/nec%20straight%20fluorescent%20lamps/biolux/biolux.htm
hope this help
