Is a watt a watt?

[The Grim Reefer]

You should worry more about whats per gallon, not watts

What size tank, especially height but length and width

what do you want to grow

What are you using to house the lights

You can get more intensity DEEPER into a tank with 324 watts of T5's than you can with 500 watts of halides.

There is no "best" light unless you are talking very tall tanks. Then you got to run with the big dogs and use 400 or 1000 watt halides.

 

[reefscape15]

watts are watts, but in dealing with ballasted lighting systems, it's not really that cut and dry. Say you have a 250watt T-5 fixture and a 250 MH fixture. They will not produce the same amount of usable light for your corals because of the different ratings in PAR, the color temp you choose, and so forth. Also, a watt is not a watt if your looking at energy usage. If you could bypass the ballast and just run different lighting off of your 120volt receptical, a 250MH fixture and a 250LED fixture would cost the same to run. Being ballasted, however, the ballast takes the 120volt source and bumps it up to usually 300-350 on MH and 600+ on flourescent lighting. So your OHMS LAW formula of watts times volts has to take the different output voltage of the ballasts

 

[reefsahoy]

Watt? I mean What? lol

 

[noboddi]

<a href=showthread.php?s=&postid=14851920#post14851920 target=_blank>Originally posted</a> by reefscape15
watts are watts, but in dealing with ballasted lighting systems, it's not really that cut and dry. Say you have a 250watt T-5 fixture and a 250 MH fixture. They will not produce the same amount of usable light for your corals because of the different ratings in PAR, the color temp you choose, and so forth. Also, a watt is not a watt if your looking at energy usage. If you could bypass the ballast and just run different lighting off of your 120volt receptical, a 250MH fixture and a 250LED fixture would cost the same to run. Being ballasted, however, the ballast takes the 120volt source and bumps it up to usually 300-350 on MH and 600+ on flourescent lighting. So your OHMS LAW formula of watts times volts has to take the different output voltage of the ballasts

Maybe you can rephrase because this doesn't make sense to me. When you say a watt is not a watt when it comes to energy usage, then you compare 250 MH and 250 LED, 250 what?

And Ohms law is amps = voltage/ohms (I=V/R)

so I'm not sure what you mean

 

[luther1200]

Just think of it like this. In your house you used to have only incandesant bulbs, anywhere from 25w-100w. Know you have those twisty flourescent bulbs that screw in. They are only 5w-30w. But a 20w (new type bulb) throws out just as much if not more light than an old 75w bulb.

So no in comparison to light output a watt is not a watt. Some fixtures are much more efficient and you get a lot more light out of each watt.

 

[dan223]

<a href=showthread.php?s=&postid=14843356#post14843356 target=_blank>Originally posted</a> by buffalo123
Yes a watt is a watt
Voltage X amperage =watts
No matter the source of voltage or the source of amperes.

Not true
this is only theory
with ac power in the real world it does not add up or work because of something called Power Factor.
I cannot tell for sure what the OP is really asking is it does 200 watts of mh really draw 200 watts compared to t5. Or is it comparing efficiency of watt per lumen or par.

 

[noboddi]

I think the talk on watts and lumens is somewhat moot, as PAR is the critical number

 

[luther1200]

I think the OP's question is, is there a difference between 500w of MH Vs. 500w of VHO. And the simple answer is yes, there is a difference. I think every body is just over complicating a simple question.

 

[TeddyK]

Hopefully I'm not being redundant, but maybe this may help some of you.


Watts
A watt is a measure of electricity consumed, and is a poor representation of lighting produced. It tends to be common word thrown out, especially with lighting sales, as you want as little wattage used while producing the most volume of light.

Lumens
Lumens are a true measurement of light, but can be misleading, since it is a measurement of light produced at it's source. While a more accurate method to measure lighting than watts, you need to keep in mind that light dissipates as it travels.

Candella
This is the best way to measure lighting at a target location as it is a measurement of the power behind the light's wavelength at a given location. Meters to measure candella run from under $100 to thousands, and then there's the issue with measuring your light under water. (I'm sure some creativity with disposable tank gloves can help, though they will filter the light as well) Not that I'm suggesting that anyone run out to grab a meter, mind you.

In the end, you need to consider what you're using to produce your lighting before you analyze the wattage. Comparing metal halide to fluorescent wattage will not help you. You'd be smarter to look at the promised lumen output of a particular lamp. Your goal would be to consume as little wattage, with as little heat production (as heat is 'wasted' energy) and the most lumen output. LED lighting does this well, but is still very expensive; however, within 10 years (if not sooner) it'll more than likely be a standard everywhere.

Keep in mind that as lamps grow old, they produce a weaker output of light. They may still consume the same amount of power, but the lighting wavelengths degenerate with prolonged use.