High Output Florescent lights

[Ray]

Originally Posted by DavidCampen

Color temperature has very little meaning when applied to fluorescent lights. When a manufacturer calls a lamp 10000K, all that means is that the manufacturer is trying to imply that this lamp will look bluer than another lamp that is said to be 6000K. As Connie said, a true blackbody radiator at 10,000K would be emitting mostly in the ultraviolet.

Once again, none of this is incorrect, but I think you may be treading a bit out of context here, David.

The "actinic" bulbs, often labeled as 10,000°K, that are intended for growing aquatic plants and especially corals, are not merely made to "look" bluer to the human eye - which is what the "corrected color temperature" is focused upon with most fluorescents. In order for there to be an appreciable amount of UV emitted, the glass used to make the tubes is higher in silica and lower in the glass modifiers than are most other bulbs. To take it beyond actinic to UV bulbs used for germicidal applications, the bulbs are pure SiO2, as it does not block the UV.