CRI

CRI: or color rendering index. This denotes how close to natural light the bulb is. The sun has a CRI of 100. Any bulb above 85 will be fine.

CRI - Color Rendering Index, Measures the color rendering ability in comparision to natural sunlight
DE - Double-ended, Refers to HQI metal halides
E39 - Standard mogul base ...

CRI; color rendering index A number used for rating lite bulbs on a scale up to 100, where 100 is equal to sunlight.
Crushed coral A Calcareous substrate material with pH buffering abilities, for marine aquaria.

CRI (color rendering index): A number used for rating lite bulbs on a scale up to 100, where 100 is equal to sunlight.

CRI (Color Rendering Index)
The color rendering index identifies the degree of color shift objects undergo when illuminated by a particular light source.

Lighting with high CRI for turtles.
FW 210's: pea gravel as substrate; logs; native FW plants. Back glass painted a sandy color. One tank set up as a small vivarium; this is where we put baby alligators and baby turtles.

>One other thing from his book is they (at least were) use 3700-4200K >MH bulb -at- 50-60% CRI. This is not the best light to view things by... >At any rate, Anthony, I'd like a (reasonably) detailed description of >the Smithsonian tank some time.

The next issue with aquarium lighting is the various terminology used in the hobby, such as color temperature measured in kelvins, color rendering index (CRI), photosynthetically active radiation (PAR) and lumens.

It's also important to look at the Color Rendition Index (CRI) rating for the bulbs used. This is a good measure of overall bulb intensity. A CRI rating in the 90's is desirable for most reef aquaria.

VHO systems require special end caps to withstand the higher heat emitted. Most of these tubes are available with internal reflectors to maximize intensity. Use bulbs with a CRI of 90-99 (CRI 100=sunlight), or color temperature of 5500-10,000K.

The Iwasaki literature states that the color temperature of this lamp is 6500K and the CRI is 96. It appears bright white over the aquarium and doesn't require supplemental lighting, unless you're a blue freak.

spectrum aquarium lighting, check out this discussion of aquarium lighting science and photosynthesis, or this aquarium light bulb comparison study. For more information on lighting metrics, check out this page on Kelvin, nanometers, PAR, and CRI.

See also: Color, Aquarium, Lighting, Plants, Water