Lighting Wattage Definition

LCDRDATA · 07/03/2008, 09:09 PM

I posted this a few minutes ago on the lighting forum, and then saw this "newby" forum and thought I'd put it here as well (I didn't see anything in the user rules about cross-posting; if this is inappropriate just let me know)

Background - We're just setting up a new reef tank (75 gallon) and trying to figure out lighting. In the meantime we have three 6500K compact fluorescents on the tank, from bulbs we've been using to replace our regular home lighting. Each of these bulbs is 26W, which is supposed to be equivalent light output to a standard 100W incandescent bulb.

Question - the generic rules of thumb are stated in terms of so many watts of lighting per gallon. However, the different possible forms of lighting have different light output per watt. So, for our current, temporary lighting, do I count the lighting as 78 watts (roughly 1 watt per gallon), or as the incandescent equivalent of 300 watts (roughly 4 watts per gallon)?

Thanks!

reefergeorge · 07/03/2008, 09:14 PM

Don't count it as anything. The 6500k will grow unwanted algae, and the 26 watts will not support any corals.
For a 75 reef, depending on what you want to keep???? I would go with either 4 or 6 54 watt t5ho lights.

Mariner · 07/03/2008, 09:22 PM

The claim that "26w = 100w of incandescent" has no validity for aquarium lighting. You have 78 watts of light.
FWIW, you CAN use 6,500K flourescent bulbs over a reef tank, but you need a mix of higher Kelvin bulbs for the best effect. For years I've run six normal output 40 watt flo. bulbs in shoplight fixtures over my 75g. I mix actinic, 10,000k, 6,500k, etc.
hope this helps,
Mariner

Percula9 · 07/03/2008, 09:57 PM

I think watts per gallon is becoming obsolete. Instead we should determine lighting based on lumen output. You can by underwater lux meters that are inexpensive.

07/03/2008, 09:09 PM	#1
LCDRDATA Registered Member Join Date: Jul 2008 Location: Northern Virginia Posts: 225	Lighting Wattage Definition I posted this a few minutes ago on the lighting forum, and then saw this "newby" forum and thought I'd put it here as well (I didn't see anything in the user rules about cross-posting; if this is inappropriate just let me know) Background - We're just setting up a new reef tank (75 gallon) and trying to figure out lighting. In the meantime we have three 6500K compact fluorescents on the tank, from bulbs we've been using to replace our regular home lighting. Each of these bulbs is 26W, which is supposed to be equivalent light output to a standard 100W incandescent bulb. Question - the generic rules of thumb are stated in terms of so many watts of lighting per gallon. However, the different possible forms of lighting have different light output per watt. So, for our current, temporary lighting, do I count the lighting as 78 watts (roughly 1 watt per gallon), or as the incandescent equivalent of 300 watts (roughly 4 watts per gallon)? Thanks!

07/03/2008, 09:14 PM	#2
reefergeorge Registered Member Join Date: Jun 2006 Location: St Louis MO Posts: 4,222	Don't count it as anything. The 6500k will grow unwanted algae, and the 26 watts will not support any corals. For a 75 reef, depending on what you want to keep???? I would go with either 4 or 6 54 watt t5ho lights. __________________ $35-50 for a <1" frag of some stupid named thing that came from a colony you bought for $40-60 wholesale and chopped into 20-40 pieces? No thanks. "JasonH" Current Tank Info: 125 aggressive reef, DIY led lighting, swc cone skimmer, 33 gallon sump, posiden Ps3 return.

07/03/2008, 09:22 PM	#3
Mariner Registered Member Join Date: Feb 2003 Location: North Alabama Posts: 3,952	The claim that "26w = 100w of incandescent" has no validity for aquarium lighting. You have 78 watts of light. FWIW, you CAN use 6,500K flourescent bulbs over a reef tank, but you need a mix of higher Kelvin bulbs for the best effect. For years I've run six normal output 40 watt flo. bulbs in shoplight fixtures over my 75g. I mix actinic, 10,000k, 6,500k, etc. hope this helps, Mariner __________________ DESIGN DEMANDS A DESIGNER. ~The perception is that perception is reality, but the reality is that it isn't. Current Tank Info: 75g mixed reef; 135g mixed reef

07/03/2008, 09:57 PM	#4
Percula9 Registered Member Join Date: Jul 2007 Location: Orange County CA Posts: 3,819	I think watts per gallon is becoming obsolete. Instead we should determine lighting based on lumen output. You can by underwater lux meters that are inexpensive.