Watt per gallon for LEDs?
 

Just curious to know what the watt per gallon requirements are to keep a anemone and sps.

Dose not apply to leds. They are more of a focus light. Putting say like 10 3watt less over a 20 gallon tank. Is like putting a 250w mh light over your tank with a lot less heat.

Sent from my SPH-D710 using Tapatalk 2

thank you!

rapid coral suggests one 3watt led per 15-20 square inches of tank surface

Thats funny. Depends on what type of lighting and look do you want? How tall is your tank? If you want a bunch of UV LEDS or if you want to compete with the colors of MH and T5 you will need to add much more. If you just want the 450 blue and 8000K look then less.

Also depends on what kind of LED. They are not all the same like say 150 MH bulbs are about the same in amount of light. It's not the same for LED lighting.

we're planning on setting up a 30g, which will hopefully contain softies, LPS, SPS and an anemone.
So what are the most cost effective LEDs?

It's not just the LED. You must also go by what wattage the LED is driven at. You can drive a 3W LED at 1W, 2W, or 3W. You must also take into account what degree optics you are using. 40/60/80 or none(120* spread).

Stevesleds Luxeon. $2.99 each and amazing customer service with fast shipping.

The combo of 2:1 Luxeon Royal Blue to Luxeon 2700k warm whites (Or 3:1 if you like the deeper blue look) is the best looking LED combo I have ever seen, and FAR better then any premade fixture I have ever heard of.

The basic rule of thumb was 1 3w LED for 15-20 square inches of surface area up to 24" deep. However, that was for Cree XT-E and XP-G driven at a max of 700mA.

The modified rule of thumb would look like this:

1 XT-E/XP-G Cree driven at 700mA per 15-20 square inches of surface area up to 24" deep

Or

1 XT-E/XP-G Cree driven at 1300mA per 22.5-30 square inches of surface area up to 24" deep

Or

1 Phillips Luxeon driven at 1000mA per 22.5-30 square inches of surface area up to 24" deep


So for a 30 gallon tank 14 Luxeon Royal Blues and 7 Luxeon 2700k Warm whites would be perfect.

Here is a post about me doing 20 LEDs in a perfecto style hood for a 29 gallon tank. its a bit ghetto (the person I built it for was on a VERY limited budget) but might give you some ideas:
http://www.reefcentral.com/forums/sh....php?t=2192354

By this logic, wouldn't a 1 watt LED be sufficient to light a 120 gallon SPS tank?

that rule does not apply to LED's. if what Buzz1329 said was true then a single 120w Led unit will not be enough for a 120 gal. LEDs are mostly directional with not much wide angle light structure. also every LED fixture has its own par reading and work/act differently.
with LED's mostly coverage is the big issue than wattage.

I wasn't saying that if you put the 10 leds only over this tank that it would be. Equal to that 150w mh. Used a par30 bulb with 5 3w leds over a 10 gallon manor tank. And everything was fine my sps, lps, and bta. And the leds were driven at 2 Watts each. That's 10 watts and the par at the bottom of my tank was higher than the 150w de I had. The light is more focused with the lens. Creating greater par near the bottom of my tank. The 150w was higher up maybe 3inches higher. Even with the mh at the same height more heat was put into my tank But par was about 50 to 25 points higher near bottom of my tank. Bug the trade off is I can run my lights all day instead of having my mh turn off during the daytime when temp gets above 82°.

Sent from my SPH-D710 using Tapatalk 2

Say if you need 50 3w leds , you would need say like 100 1w leds to get the same amount light. Just a guess! But some of the first commercial led lights used 1w leds. Compared to most newer ones running 3w or higher less. I think ecotech runs 10w or 30w leds

Sent from my SPH-D710 using Tapatalk 2

Ecotech Radion uses 3W LEDs, some of which run at 5W. The point of LED fixture design is to make it as reliable and economical to run and manufacture as possible. Sure its possible to light a tank with 1W or 1/2W LEDs, but the most efficient LED emitters in terms of lumens per Watt happen to be the 3W. Having to solder and interconnect 3 times as many LEDs, while decreasing the overall fixture efficiency hardy makes sense.