Light comparison

I've read everywhere about a certain number of watts per gallon for light in order to grow plants, coral, etc and so far it's been helpful, but it's always related to fluorescent light. Is there a difference in light output between t8, t5, and t5ho light output per watt? How does light/watt of fluorescent compare to incandescent? To led? To metal halide?

Better yet, is there a great website that you can link to that would save time in replying and answer all these noob questions?

Here is a post that lists many articles. You'll find in these articles two about lighting. Invertebrate Lighting and Coral Lighting. Both will be good reads.

http://www.etakc.com/t168-new-to-saltwater?highlight=new+to+saltwater

To help with your specific situation, let us know the dimensions of the tank you're trying to light, the type of light source (T5, MH, LED, ect) and the specific type of coral you're wanting to keep. It does sound like your current research has been dated.

For current purposes, I want to grow some plants in an eclipse 12. I found the marineland 17" hidden led light bar. It has 56 white lights at 6500K and 16 blue lights (420nm?). Linens are low at 400, but light in the tank appears quite bright. Drsfostersmith reports 25par at 12" which is great for a $40 in-hood retrofit in a tank growing java moss and java fern in brackish conditions. If I get into saltwater, I'd probably be spending much more on quality light.

Okay. Well oddly enough I don't know the first thing about freshwater lighting! Haha. I'm completely out of my league there.

25par is extremely low for any sort of saltwater application, but freshwater is TOTALLY different. Images are a poor evaluator of light intensity.

http://open-reef.com/phpbb/viewtopic.php?f=4&t=22

this is salt water again but the more you know...

this is a bit more in depth:
http://www.americanaquariumproducts.com/Aquarium_Lighting.html

I would apply the knowledge gained from the second link to the specification of the lights your looking to use, and also what conditions the plants your growing prefer

Fairly Early into the read, i recommend a cup of coffee and a full read :

"Plant chlorophyll absorbs light at wavelengths of 300 to 700 nm Kelvin rating of about 6400 strikes a good balance here, which is why this is the best Kelvin temperature for freshwater plants (and symbiotic zooxanthellae in corals in shallow, perfect conditions)."

yea that second article is good I have read that a few times even after that I am playing with light adjustment.