watt vs lumens vs foot candle vs....

[Luis]

Is not very ambiguous to measure lighting in watts? is not the same 1 watt of incandescent, fluorescent (T8, t5, pc...) or 1 watt used for metal halides. Why don't we start using lumens or footcandles or something else that could represent better what we are talking about.

By the way : how many PC bulbs do I need to use to replace 10 bulbs of regular fluorescent (same size.... lets say 24 in long ) .

Thanks

 

[reefman225gal]

I dont know if i understand your question but if you think that the bulbs you mentioned were all at the same watts they would be equal thats not true a 175 watt halide would put out much more light then a 175 watts of fluorescents. and for you second question (10)- 24 inch fluorscentnts is about 200 watts if they are the 20 watt ones and most pc lighting at 24 inch fixtures will be about 130 watts (2- 65 watt bulbs) but you can get a retro kit (DIY) add another 65 watt bulb that will give a 195 watts and like i said the pc bulb will put out more light so 195 watts of pc will be brighter then the 200 watt fluorscents.

 

[Len]

The way I view it is: watts are used because it describes the electrical application, not to describe the amount of light from the output device. Now granted, there is a correlation between power and output (lumens, PPFD, etc.) and this correlation isn't very linear, but we still need to use watts to know what kind of bulb we can use in a given application.

I think 2 to 3 PCs to replace 10 NO bulbs of similar length. A PC is essentially two T5 bulbs linked together. T5 is more efficient then T8 is more efficient then T12 - plus the thinner diameter tubes are usually driven with more ma - so a few less T5s would be needed to replace T8 or T12 NOs.

 

[ChrisRD]

Is not very ambiguous to measure lighting in watts? is not the same 1 watt of incandescent, fluorescent (T8, t5, pc...) or 1 watt used for metal halides. Why don't we start using lumens or footcandles or something else that could represent better what we are talking about.

Yes, watts are a poor indicator of light output. Lumens, footcandles, etc. give a better idea, but PAR is a more useful indicator for our purposes (since our primary interest is photosynthesis). That said, intensity is only part of the issue - spectral output is also a concern for most reefers.

Also keep in mind that reflectors play a very big role in how much light will actually get to the target animals, so knowing the output of the lamps alone only gives you part of the picture.

It's a complex topic which is probably why there is so much debate/confusion in the hobby when it comes to lighting...

Check out Sanjay's site for lots more info on these topics:
http://www.reeflightinginfo.arvixe.com/

HTH

 

[Luis]

Yes, that's exactly what I meant... Thank you for your replies. Yes i know spectrum is very important but could be better if we start using another unit when we are talking about light... thanks for the link I haven't read it but I will.


Thank you again.