How Many Watts Of Lighting Do I Need?

[MrG09]

when watts are stated for the tubes and eg are aiming for 100 watts is that actuall wattage or the incandescant wattage equivalent? eg normal household tubes an 11 watt tube would give as much light as say a 60 watt incandescant bulb or would i be aiming for 100 watts as stated on the tube?
might sound like a silly question but im just a little confused so any help appreciated if anyone understands that lot ?

 

[aaronnorth]

the wattage stated on the tube is what you should take. Also take into account the diameter (T5, T8 etc)

 

[SuperColey1]

If you are aiming for 2WPG over a 10USG tank then you want 20W of T12 with a reflector on top going by the WPG rule. The 'equivalent' is no such thing. A flourescent 11W being equal to a 60W incandescent only means to the human eye it looks as bright as a 60W light.

However that is Lumens, Watts are power. Neither are an actual measurement of light. W is a measure of how much the tube should take at peak. Lumens is how bright the light appears. These 2 are the input and output measurements for humans purposes

The actual light measurement is PAR/PUR and this has so many variables that a manufacturer couldn't put this on the packaging. Meters cost a fortune so are out of the hobbiest's reach so we go by W as it is printed on every tube/packaging.

Then we come to the tubes. The WPG was calculated on T12 tubes. Technology has moved on and we now have gone from T8 to T5/T5HO/PC/PL to LED etc. Each in turn getting 'brighter' and more efficient than the previous so that throws the WPG rule up in the air really. BESt to say that 2 full length T8s under reflectors will grow anything with CO2. T5 a little less W is needed. LED much less etc. etc.

So in essence go by the W assuming you are using proper reflectors and forget about too many calculations

AC