# When does WPG apply?



## Darksome (Feb 15, 2009)

I have two T8 14watt bulbs over my 10 gallon tank...which would give me 2.8wpg...I have read article after article of how the wpg rule only applies to T5 bulbs and how the rule breaks down with tanks <10 gallons and >75. Can someone please care to explain in what way the rule breaks down?

I know the height of the tank is taken into consideration. If I don't have 2.8wpg, how many do I have exactly?

For the moment I mostly have java ferns in the tank with some ludwigia repens waiting to see whether it will thrive...planning on adding some rotala rotundifolia and pygmy chain swords that I'm currently cultivating by the window.


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## TAB (Feb 7, 2009)

it really never does.

I've ran tanks that were 40+ watts per gallon( yes 40) and I did not have enough light. I've also ran tanks with 1.5 where I had too much.


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## jschall (Apr 13, 2009)

TAB said:


> I've ran tanks that were 40+ watts per gallon


... how does that work? Was the tank like 8 feet deep?


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## Newt (Apr 1, 2004)

Read the sticky on this topic located in this forum.


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## Darksome (Feb 15, 2009)

TAB, I'm starting to think that myself. What's the point of making a rule when it is not going to be reliable?

Newt, I've read that thread several times and I still haven't found the answer to my question...it says the same thing, 10 gallon tank would need more watts which also contradicts what I have read elsewhere...it just doesn't make any sense...there's no consensus to it whatsoever.


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## TAB (Feb 7, 2009)

jschall said:


> ... how does that work? Was the tank like 8 feet deep?


standard 10 gallon with a 400 se and 2x 32 watt PCs. only prob I had was cooling. The ice probe thermoelectric chiller was not enough. my ATO was doing almost 2 gallons a day.


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