# Questions about "watts per gallon" calculations



## kperera (Jul 12, 2011)

The internal dimensions of my tank are 65.5" long x 13" tall x 12.75" wide. I have a 3" layer of Eco-Complete, and the water level is at 0.5" from the top, so the height of the water column is only 9.5". So the total internal volume of the tank is 47 gallons and the volume of water is 34 gallons. Which of these two volumes do I use in calculating "watts per gallon"?

Also, I am using LED strip lighting for my tank. The strip is 66" long, suspended 2" above the water surface, has a 120 deg beam angle, a total output of 1600 Lumens, a color temperature of 5000K, and uses 24 watts of power. What would be my "T12 equivalent wattage" for the purpose of calculating "watts per gallon" for my tank?


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## jcgd (Feb 18, 2004)

You don't use watts per gallon. To get accurate light levels by trying to convert back to an outdated guideline you will need to take par measurements to compare. If you take par reading you might as well stop there because that is what you want to do.


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## kperera (Jul 12, 2011)

So, without a PAR meter, what can I do to get an idea of what type of light I have? I am just trying to figure out what type of plants will be suitable for my tank. I see plants as being classified as low, medium, or high light. Is there a way to figure out my light level, without using a PAR meter?


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## jdm68 (Jun 2, 2011)

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


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