# T5 lighting vs WPG question



## destructo (Aug 12, 2009)

I have a question about lighting. With the whole WPG rule I am confused as to how it compares to T5 lighting, I know the whole rule was brought up with T8 and T12's but what about T5?

The only reason I ask is because I have a Coralife 36" T5 light over a 35gal tank and with 2, 21watt lights that is only giving me 1.2WPG.

I do have some good growth in the tank but wondering if it would be worth it to get another fixture in the future if what I have is not enough.


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## Harry Muscle (Mar 21, 2007)

destructo said:


> I have a question about lighting. With the whole WPG rule I am confused as to how it compares to T5 lighting, I know the whole rule was brought up with T8 and T12's but what about T5?
> 
> The only reason I ask is because I have a Coralife 36" T5 light over a 35gal tank and with 2, 21watt lights that is only giving me 1.2WPG.
> 
> I do have some good growth in the tank but wondering if it would be worth it to get another fixture in the future if what I have is not enough.


First suggestion, ignore and forget Watts Per Gallon, it doesn't work for any of the lights we use now. Instead have a look here, it will help you estimate the amount of light you have and give you proper light measurements in PAR:

http://www.plantedtank.net/forums/lighting/105774-par-vs-distance-t5-t12-pc.html

On the second page the graph is slightly revised so I suggest scrolling through the whole thread (it's only 3 pages).

Enjoy,
Harry


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## destructo (Aug 12, 2009)

Thanks for that link

If I did the graph right I should be in the medium category (just barely) as my tank is 18 inches high and with T5 NO its just touching the medium light.


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