# 2 Watts per US or UK gallon?



## Ryan! (Jan 21, 2007)

What gallon are we talking about here just to be sure? 
Doesn't metric make sense?


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## dennis (Mar 1, 2004)

US vs. UK gallons makes no difference here. There are 1.2 US gal for 1 UK gallon. Aquariums rarely hold the right amount of water for their name. A 29 US gallon All-Glass aquarium actually holds 25 if you do the math. A 50 gallon held 46. The watt per gallon rule is a generalized concept anyway, more a guideline than a rule. Thinking of wpg in terms of liters is perfectly fine but you won't improve or remove accuracy by it. There are 3.785 liters in one US gallon and 4.546liters in 1 UK gallon.

Again, a rough guide to follow.


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## Tentacles (Jun 25, 2006)

I'm with you Ryan... I think the world is too small a place to be mucking around with gallons at all!

Here's some links so you can figure out the strange olde speake that goes on here:

First tank guide - tank volume calculator

Koko's Goldfish World - Volume and temp converter


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## Mr Fishies (Apr 9, 2006)

dennis said:


> <SNIP> Aquariums rarely hold the right amount of water for their name. A 29 US gallon All-Glass aquarium actually holds 25 if you do the math. A 50 gallon held 46. <SNIP>


I think if you calculate the displacement volume of the tank (including the thickness of the glass) they seem to work out. The volume is always off by the thickness of the glass. If my math is right, my 50G tank, includes 4.6 *gallons of 3/8 in glass*

External: 36x18x18 = 11664 in/3 = 50.5G
Internal: 35.25x17.25x17.25 = 10489.078125 in/3 = 45.4G

Seems marketers will always sell you the biggest number they can support in an argument...but in my mind, to volume of something I buy should be what it can hold, not what is displaces!


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## mrmujtaba07 (Jun 9, 2019)

Gallons For what purpose 
here i just want to make sure about it. But Anyways i want to list here a usefull page where you can calculate gallons, Aquarium Sizes, Tank Dimensions,Length, Width, Height & Weights

All these calculations are listed and discussed in a single spot...
Resource: Mr Fish Keeper


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## hoppycalif (Apr 7, 2005)

Watts per gallon was never an accurate way to judge light, unless you had a tank with the standard geometry, and were using T8 fluorescent bulb lights, sitting right on top of the tank. For more information see: https://www.plantedtank.net/forums/10-lighting/184368-lighting-aquarium-par-instead-watts.html


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