# LED lighting and watts per gallon - confusion



## jeffkrol (Jun 5, 2013)

Aqua07 said:


> Hi folks:
> 
> Ok, I"m new to LED fixtures and have a question regards to light intensity per gallon. I ordered a Chihiros C light fixture:
> 
> ...


w/Gal "rule" was never a very good rule..

THAT said, and for the sake of simplicity.. consider 1/2W LED = 1W t5/8/12

DEFINITELY doesn't hold for deep/shallow and/or wide tanks..


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## Aqua07 (Jul 9, 2012)

Great thanks. So then in my case, I have 28 Watts of light arsenal.



jeffkrol said:


> w/Gal "rule" was never a very good rule..
> 
> THAT said, and for the sake of simplicity.. consider 1/2W LED = 1W t5/8/12
> 
> DEFINITELY doesn't hold for deep/shallow and/or wide tanks..


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## jimclassic (Dec 14, 2017)

Is 9W x 2 LEDS ok for 20 gallon tank?


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## skanderson (Jul 25, 2010)

that depends on what you want to keep in the tank and what type of leds they are. my rule of thumb which has held up through 5 different led builds is that 1 watt per gallon of decently efficient leds, think over 100 lumens/watt. will let me grow most anything I want in that tank/terrarium. the problem with 2 emitters over a 20g tank could end up being that there is a lot of shading. remember leds are point emitters.


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## bud40oz (Dec 9, 2017)

not all led diodes are equal, some cheap ones are only .5 watts while higher end ones now days i think are pushing 5 watts. cree led diodes are some of the best, most cheap led strip lights don't use these. if you spend a few hours researching and google. you could probably come up with a really nice diy led for a pretty cheap price


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