Watts on, Watts off

JohnO · 01-31-2005, 11:09 PM

Over time I have read what a lot of people quote or ask about how many watts per Gallon ( WPG ) they have, or they need for their respective tanks.

Personally I have always disliked this 'rule' as I think it is misleading and in fact totally inappropriate. My reasons are as follows:

Watts are a unit of electricity, not a unit of light and because different lighting types ( eg NO, MH etc ) deliver different amounts of light for the same amount of Watts then the 'rule'is very misleading.

WPG does not take into account water depth or the height of the light source.

I mean if you wanted to boil water to make some coffee then WPG could be useful, but as a measure for light requirements I think it is totally useless.

Love to here what YOU think :-)

John

Craig Manoukian · 02-01-2005, 12:00 AM

Let's discuss the PAR value as a measure of intensity.

I agree that WPG has a limited and general application at best.

Gresham · 02-01-2005, 03:51 AM

BAh, I just wrote a an entire noval on this and lost it when I tried to post it and found out I had lost my WIFI signal, and my post. Arg. Maybe tommorow I will hash it out yet again.

Speedy · 02-01-2005, 06:03 AM

I agree that watts per gallon has it's limitations as well. *But I think it is easier to understand that 5 watts per gallon on VHO's or PC will keep corals alive at 6 inches from the surface.

I just think that the technology to measure PAR, PPFD, Lux, µMols·m2·sec, *needs to be simplified, mass produced, and made accessible to low-medium budget aquarist before we can suggest lighting measures in *these units.

mojoreef · 02-01-2005, 07:49 AM

Wpg is pretty much as useless as the saying its all about the intencity. In order to judge lighting you have to look at the whole picture. A bulb can be the ultimate in intencity but have no effect on a coral. Same could be said for a bulb that had all the perfect range of temp but didnt have the intencity to drive the light to the corals. Vho's and PC' have good color temp but lack the intencity to drive the light very deep. Will they grow coral??..yep for sure. Will they color up coral? to a point for sure.
Now in saying that IMHO most all MH's sold in this hobby will grow and color coral up to a point, so it is kind of mute unless someone want to take it a little deeper and talk about how the coral uses light, what the coral needs for temp and what makes what colors come out.

John when we were talking in the other thread I was kind of talking about the above, how they use it and what makes different colors come out. I should have pmed ya.

MIke

Diver_1298 · 02-01-2005, 08:34 AM

Has anyone noticed that there is no "Important Topics"
thread under reef lighting. Maybe this discussion should be under that heading. PAR, Lumens, Watts, WHAT??
Watts per Gallon is the easiest way for someone to describe the way to light a tank because... It's a label on the bulb. Be it Metal Halide or a Fluorescent. You could talk PAR or Lumens or Spectral energy or Newton Meters to someone all day long and all you would get is a blank look. If you mention WATTS, then a light bulb turns on and their face brightens up because you're talking something that they have heard about and maybe even slightly understand.
So to make a long story even longer. What is important? The amount of useful light that reaches the Corals and animals that require it and it's intensity. Now how do you explain this to a Layperson and when are the lighting manufacturers going to start marking the bulbs with PAR values written on the side next to the wattage.

Definition - PAR photosynthetically active radiation is a measure of the amount of radiation capable of driving photosynthesis striking a unit area. It is given in the units of micro moles per meter squared per second (umol/m2/s).
In the applied plant sciences such as plant ecology and agronomy, there is a need for a simple system for measuring the light which is active in plant growth, analogous to the photometric system for measuring the light which is useful to humans in their daily life. The best likely candidate is "photosynthetically active radiation" (PAR).

Now ask yourself if you truly understand this definition and then ask yourself if the average person walking into a pet store for fish or live rock would understand it.

So debate all you want. Until they start handing out PAR meters like candy, or a PAR value at a rated distance on the side of the bulb packaging, you're gonna have to live with WPG.

Jim

Speedy · 02-01-2005, 08:43 AM

Ahem, yes taking this deeper is possible, however, I know that the means aren't easy to come by. *

It would also involve a long strenuous process.

I guess we could use educational (universities with Marine bio dept) sites to post questions (or surf through research) on the demands of different species of zooxanthellae. *Incredibly enough it seems these microscopic symbiont algae are the backbone of all or most of our reefs. *

They provide the color and food for our photosynthetic creatures. * And are the reason we spend hundreds on lighting our tanks, and hours debating whether we spent our money wisely.

I suggest we start with one species of coral or maybe even a clam. *And find out what species of zooxanthellae it hosts. *Then move our research from there. *Find how to supply the demands for that species of zooxanthellae and find out what other coral species host similar zooxanthellae.

Then we'll not only be geniuses but we'll have super reefs at our homes. * *

Speedy · 02-01-2005, 08:52 AM

[quote author=Diver_1298 link=board=lighting;num=1107241757;start=0#5 date=02/01/05 at 11:34:47]So debate all you want. Until they start handing out PAR meters like candy, or a PAR value at a rated distance on the side of the bulb packaging, you're gonna have to live with WPG.
[/quote]

[smiley=beer.gif]

Well said. That's precisely what I was thinking. Now if you wanna know accurately, because you want the most accurate lighting. and because your not the average person walking into a fish store trying to buy a damsel to make friends with your goldfish. Then I'm up for the research I posted above. It would be a long tedious process but it's the only way to know without going trial and error, or using the scientific method to test out all the bulbs and lamp on the market against all coral species. I think.

Birdlady · 02-01-2005, 09:10 AM

[smiley=help.gif] [smiley=sleeping.gif] [smiley=sleeping.gif] [smiley=sleeping.gif]

JUST JOKING!!! While I will not pretend to understand any of what was just said....this is a good topic to try and learn. Make sure to keep some stuff on my level!

mojoreef · 02-01-2005, 09:39 AM

Quote:

So debate all you want. Until they start handing out PAR meters like candy, or a PAR value at a rated distance on the side of the bulb packaging, you're gonna have to live with WPG.

I agree Jim its just one of those hobby terms that this hobby is riddled with, kinda boring and doesnt really pertain. So let move on to something more interesting

Quote:

Ahem, yes taking this deeper is possible, however, I know that the means aren't easy to come by.

No problem we can do it easy

Quote:

They provide the color and food for our photosynthetic creatures. And are the reason we spend hundreds on lighting our tanks, and hours debating whether we spent our money wisely.

You betca David!! although they dont really provide the color we are looking for they do produce some.

Quote:

I suggest we start with one species of coral or maybe even a clam. And find out what species of zooxanthellae it hosts. Then move our research from there. Find how to supply the demands for that species of zooxanthellae and find out what other coral species host similar zooxanthellae.

David zoox strains are not all that different. Its more of a tolence and adaptability thing and to be truely honest its not even a zoox thing....Think pigments!!!!!!!!!! those are the things that make it all happen.

mike