Actual Watts Or Equivalent Watts?

[jmeeter]

When determining watts-per-gallon, do you measure the actual wattage of the lights or the equivalent? For instance, I have 3 24" fluorescent tubes over my tank. They are only 17 watts each but put out the light equivalent of a 60 watt bulb (each). Which do I use?

 

[aaronnorth]

I would go with actual watts because they are 17w, but just as bight as a 60w.

 

[aaronnorth]

it would be better to work in lumens rather than watts

 

[three-fingers]

The watts-per-gallon rule is very, very flawed IMO. When I use it as a guideline, I think of T8 tubes.

What type of light tubes are they?

 

[SuperColey1]

When you use the WPG rul you should be thinking of T12 not T8 as the rule was calculated on T12. T8 will be slightly better than the WPG rule, PC/CF/T6 better still, T5 a lot better and T5HO as much as 2 x the WPG rule. there is no real calculation of the efficiency differences.

Best to just assume that you have more than you think these days.

AC