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View Full Version : whats the WPG rating?



Nathan
Tue Sep 19, 2006, 05:09 AM
yea just curious as to what the WPG is for lights an how its worked out, any info would be great

thanx

duck
Tue Sep 19, 2006, 05:18 AM
WPG Watts Per (US)Gallons
To work it out You need to know the tank volume in (US)Gallons then you divide that by the total amount of lighing watts
50 gallon tnak
200 watts of lighting
= 4WPG

This is very general rule mainly fo tanks 20-75 gallons in size the bigger smaller tanks and larger tanks it doesn't work.

duck
Tue Sep 19, 2006, 05:27 AM
This is very general rule mainly fo tanks 20-75 gallons in size the bigger smaller tanks and larger tanks it doesn't work.
Can't seem to find the edit button,Doesn't make sense what i wrote so here it is again.
For Bigger tanks and smaller tanks the WPG doesn't work very well,It's a very general rule nothing to live by.

Stingray
Tue Sep 19, 2006, 11:59 AM
WPG is only used by hobbyists in one country, the USA. The rest of the world does not use gallons or anything else associated with the old defunct imperial system, and they do not recognise WPG. In Australia and the rest of the world (except USA), watts per litre (w/p/l) is the measurement used as a guide for hobbyists. The general rule for hobbyists is 0.4 w/p/l is required for planted tanks.

ellwa
Tue Sep 19, 2006, 12:31 PM
I think many here will disagree

we use wpg alot around here.

2wpg is good for plants

duck
Wed Sep 20, 2006, 12:05 AM
WPG is only used by hobbyists in one country, the USA. The rest of the world does not use gallons or anything else associated with the old defunct imperial system, and they do not recognise WPG. In Australia and the rest of the world (except USA), watts per litre (w/p/l) is the measurement used as a guide for hobbyists. The general rule for hobbyists is 0.4 w/p/l is required for planted tanks.

Ok Now if i was to do some math here like 0.4x3.65(USG)=1.46WPG
It's a VERY general rule nothing to live or die by.
WPL or WPG It's not to hard to work out,In the end they work out the same.
And i have seen it at 0.5WPL

Stingray
Wed Sep 20, 2006, 03:38 AM
Not that I ever do the conversion, but I think it is 3.78L to the US gallon and 4.54L to the old imperial (UK) gallon. It can be handy to know WPG if your hopping onto US forums, but even then I am not very impressed with the info on US websites. There are a lot of inexperienced hobbyists giving their opinions and views on these US forum's and I find there is very little to learn from the US websites. For instance, their whole WPG ratings are seriously flawed IMO. To suggest a need of 4 or 5 WPG is ridiculous for a planted tank, unless you are using Compact fluorescents which are the least efficient of all lighting systems, in which case you may need 3 WPG max.
It is much easier to know your watts per litre and 0.4 w/p/l will allow you to grow most plants. Going up to 0.6 w/p/l is alot of lighting and with this intensity you will be able grow anything you like. It all depends on your tank size and what you want to achieve.

Stingray
Wed Sep 20, 2006, 03:41 AM
Not that I ever do the conversion, but I think it is 3.78L to the US gallon and 4.54L to the old imperial (UK) gallon. It can be handy to know WPG if your hopping onto US forums, but even then I am not very impressed with the info on US hobbyist websites. There are a lot of inexperienced hobbyists giving their opinions and views on these US forums and I find there is very little to learn from the US websites. For instance, their whole WPG suggested ratings are seriously flawed IMO. To suggest a need of 4 or 5 WPG is ridiculous for a planted tank, unless you are using Compact fluorescents which are the least efficient of all lighting systems, in which case you may need 3 WPG max.
It is much easier to know your watts per litre and 0.4 w/p/l will allow you to grow most plants. Going up to 0.6 w/p/l is alot of lighting and with this intensity you will be able grow anything you like. It all depends on your tank size and what you want to achieve.

duck
Wed Sep 20, 2006, 04:18 AM
Been on the US forums quite a bit there is only one i found not to bad.
I can't recall reading that or that it been said that you need 4+WPG on this paticular forum which i agree is over the top, but then again i running 4+ myself.
The one i frequent suggest anything from 2 as a min-3.5 WPG as the max,there only a couple of aussie forums for planted tanks which i can't link,They aren't to bad, trying not take on the US style of thing's.
But keep in mind this rule only really works on 20-80(USG)60liter-350liter's very roughly,Anything bigger or smaller you can throw it out the window basicly.