<a href=showthread.php?s=&postid=8883030#post8883030 target=_blank>Originally posted</a> by jmchzn
More energy into the room...what does that mean? The air blowing out of the side of SOLARIS is never more than 84 degrees! More of the 375 watts actually goes in the tank directly where it's used and needed as opposed to the MH set up which lit the whole freakin room. My room is dark except where the tank stands. No light on the walls, floor or cieling just in the tank. I would think the 375w is MORE USEABLE LIGHT. Not scientific you say but my tank at 4 months old looks better than 50% of all posted pics on this site and I'm being generous! AS soon as I figure out how to shoot the tank I'll post a pic and you be the judge. So the only real question with MY light is how will it hold up long term? What will actual bulb replacement cost?
Energy = Heat
375W is 375W Light spill is a function of the relfector design. The visible light is only part of the energy. You are correct, the LEDs do give off more of their energy in the form of visible (to the human eye) light. However everything radiated from the bulb falls someplace on the electromagnetic spectrum.
Your microwave heats food, but you can not see the "light".
UV light causes plastics to yellow, but you can not see the "light".
Blue light is visible but has much less photosynthetic use than yellow light.
Black and White film is not sensitive to RED light.
Digital camera sensors do not see some laser lights.
etc
You speak of usable light... PAR is one of the ways we can look at a given light source and determien how much "usable" light it contains for corals or plants.
The wavelength of the light has a lot to do with how deep it can penetrate into a body of water. Some light sources are able to penetrate deep into a tank, others not as deep. The wavelength and intensity govern how far the light travels into the water. The LEDs do have some issues with regards to the intensity and the depth.
Yes, the bulb life and replacment cost are something that surely will need to be monitored. I would suggest (not just for you PFO guys) a PAR meter to track the fixtures intensity over the life of the installation. We spend all of this time trying to save money and get the most out of our lights, but then run the bulbs until they are 50% or less efficient.
Bean