K數大概比較能代表視覺感受
目前國外比較長提及的單位應該是PAR
一般來說PAR比較高的為 6500K-10000K 的燈管
如果要選14000K以上的燈管要注意PAR的差異很大
有興趣的可以參考看看，還有文中的相關連結
mE/s/m2 (microEinstein/m2/second; PAR; PPFD)
A microeinstein per second per square meter (mE/s/m2 or mE/s*/m2) is a unit of light energy per second landing on (or passing through) a given area (Figure 2). Photosynthetically active radiation (that is, light in the 400 nm – 700 nm wavelength range; PAR) can be given in energy terms as PAR irradiance, which is the total energy in the 400-700 nm range. In that case, the units of PAR are watt/m2. It can also be measured in terms of photons. In that case, PAR is called Photosynthetic Photon Flux Density (PPFD). PPFD is a measure of the actual number of photons in the 400 nm to 700 nm wavelength range that are incident per time unit on a surface unit. When expressed in PPFD, all photons are equivalent regardless of their energy and consequently, PPFD is measured in microEinstein/m2/second. A calculator for various light-related units can be found here. An article with detailed information on such lighting units and their application for reef aquarists can be found here.
摘錄於本期reefkeeping http://reefkeeping.com/issues/2005-08/rhf/index.php
