Could someone answer a silly question for me?
- Thread starter caseykell21
- Start date
Photosynthetically Available Radiation. Without going into all the ugly details, it's a measure of how much usable light a bulb puts out (actually, it is measured as how much hits a surface). More PAR = more effective illumination. In general, the higher the color temperature, the lower the PAR value. 10000 K produces more PAR than 20000 K, for example. Actinics don't have an actual color temperature, but they produce PAR like a very high kelvin bulb.
AS for clams not being able to live in those light conditions, i actually saw what i think was a crocea at the LFS and it was running under compact fluros, about 180 watts i think the manager said. i then later asked Calfo if the clam would be happy in the lighting, and he said it is probably a lower light demanding species and it would be fine. So i think you could run a clam in your tank.
i bought a tridacna derosa that has lived over a year with a 4 foot 260 watt pc fixture in a 6 foot tank. but all the crocea clams at the lfs i bought it from die with the same light fixture in a 55 gallon tank.
the tridacna clams are usually a pale tan with stipes of brown running through them. mine has a soft purple hue to the very edge of it. most people want the bright purple/blue/green glowing and i think they are the ones that need the higher intensity light.
I specifically mentioned crocea because it's the most demanding of the tridacnids. I have seen several examples of derasa doing well under PC lights, but can't remember having seen a healthy crocea under anything beside halides. T5s would probably work, though.
