How much wattage per gallon is this

[GoldLenny]

lumens is completely useless unless comparing the exact same bulbs in the exact same reflector. say a 27 watt ge daylight cfl vs. a 9 watt ge daylight cfl in identical clamp lamps.

by telling us what watts and what type of lighting we can get a general idea. work from others experience, etc.. not perfect, but it's something everyone (even newbies) can figure out/answer.

if you're even considering using spectrum as a means you might as well just skip straight to par and pur numbers.

there are numbers/graphs that can give us more of the story but not everybody can understand how to put it together or afford/justify the meters necessary.

still... manufacturers are commonly completely off on their posted spectrums and so we couldn't go by them almost at all.

then we don't know at what point each bulb is rated for in their life cycle. (is it supposed to be 800 lumens brand new, after a burn in period, once it's burnt it's useful gasses up, when?...)

SO... we either trust the experience of others or spend $250 - $350 on a cheap par meter and post our results according to micromols at specific spots.

PAR; photosynthetically active radiation... in laymans terms; light that can be used for photosynthesis

How can you say "lumens is completely useless" unless you're a former President and it depends on what the definition of "is" is?

Lumens are the industry standard for comparing the light output of bulbs. It's what everyone is using to compare light output from cross-type bulbs.. like comparing the light output from an incandescent bulb to a CFL to an LED. You can't compare watts on these three bulbs as the same amount of lumens will be had for a much lower wattage between the incandescent and the CFL and then between the CFL and the LED. Even when comparing two identical bulb types with the same listed wattage and kelvin rating, one bulb could put out 750 lumens and the other bulb could put out 1250 lumens so the second bulb would be 65%+ BRIGHTER than the first bulb. Wattage IS useless when comparing bulbs... unless you want to know how much electricity they will use when turned on.

Yes, some manufacturers will fudge their stats... just as I'm sure some manufacturers have fudged their stats when it comes to watts and Kelvin ratings but since most folks do not have a light meter, you kind of have to rely on what is provided by the manufacturer or if an independent lab tests the bulbs.

The same could be said about dietary content on every food item we eat... but we still kind of rely on the labels to give us a general idea of what is in the food item.

To further PROVE my point... do a Google search and you'll find that the FTC is mandating improved labeling on lighting products and LUMENS will be the baseline that ALL lighting will be compared. I would give you the link but that would make it too easy for you. I'll PM the link to the OP.

Edit...

I will make it a little easier for you. Here's the title of the FTC article.

Coming in 2011: New Labels for Light Bulb Packaging

Labels Will Emphasize Lumens, Not Watts, as a Measure of Bulb Brightness

 

[dundadundun]

lumens is perceivable light in all directions in total... nothing to do with what's going down. an 800 lumen bulb could put less than 300 lumens into a tank without the right reflectors very easily... certainly tells us nothing about what's getting to any plant.

lumens is light PERCEIVABLE TO THE HUMAN EYE... plants don't care what we can see.

lumens can be quite high without putting out much for par.

bulbs can be rated at any point in their lives as to what the lumens can be. 800 lumens might be on a brand new bulb, a 2 week old bulb, a 6 month old bulb, etc., etc.. a properly burnt in bulb (3 days to 2 weeks burn-in period) will give a noticeable difference in light output... not only to our eyes but to plants also.

theoretically it's a better measure than watts... but theory and application are different worlds... so some theories need to be thrown out.

you don't have to prove or illustrate anything to me, lenny. never had to...

improved labeling in this country is a joke and has been since the government came up with the idea for food and building materials. i would explain but we don't need every thread on a/c going completely off-topic. i thought we were talking about lights.

while we're making things easy... http://www.google.com/search?um=1&h...=lumen+def&gs_rfai=&pbx=1&fp=280187d6f0589da0 ... but make sure to look at the whole picture. anybody can pick out only what they want to hear to make a point.

http://www.uvguide.co.uk/
http://www.littlegreenhouse.com/guide3.shtml
http://www.sunmastergrowlamps.com/SunmLightandPlants.html
http://www.homeharvest.com/whichgrowlightisrightforme.htm
http://extension.missouri.edu/publications/DisplayPub.aspx?P=G6515
http://www.bcb.uwc.ac.za/ecotree/photosynthesis/spectrum.htm
http://www.waynesthisandthat.com/fluorescent.html
http://www.exoticrainforest.com/Will green light kill.html
http://www.plantedtank.net/forums/lighting/97622-par-data-selecting-t5ho-light.html
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html
http://www.aquaticplantcentral.com/forumapc/apc-polls/16608-light-spectrum-do-you-prefer.html
http://retirees.uwaterloo.ca/~jerry/orchids/light.html
http://www.plantedtank.net/forums/lighting/105774-par-vs-distance-t5-t12-pc.html
http://www.aquariacentral.com/forums/showthread.php?t=173181
http://www.aquariacentral.com/forums/showthread.php?p=2393902#post2393902
http://www.aquariacentral.com/forums/showthread.php?t=217694
http://www.aquariacentral.com/forums/showthread.php?t=147012&highlight=cfl

i have looked into lighting a little... and i've read every page/link in every page i listed.

information on lumens already exists on most bulbs packaging. not sure what your point is about new labeling.

 

[GoldLenny]

Dun,

The OP asked about watts per gallon. Watts per gallon is a completely useless comparative factor unless you want to know how much electricity the bulbs are using. Watts per gallon gives nothing else.

I gave the OP information about lumens and kelvin ratings as those two numbers are readily available and are better for comparing commonly available light bulbs of different types. Most bulbs do NOT list PAR values, whereas they do list lumens and kelvin ratings... and those two factors can be used by anybody to at least get a reasonably good bulb for their intended purpose.... and be able to compare prices to get the best price for the bulb that best fits their intended purpose.

 

[jpappy789]

At 1.5-2 wpg of T5 lighting you should be able to grow most plants. That's all you need to know.

 

[Chrisinator]

At 1.5-2 wpg of T5 lighting you should be able to grow most plants. That's all you need to know.

The word of the wise, pappydew!!

 

[dundadundun]

i understand that. what the op really wants to know is "will this light grow this plant?".

the answer is.... probably. 6700k and 10000k are usually safe bets.

doesn't mean they produce the best par. just that light is in that range, visibly.

the wattage coming from the fixture/bulb is going to be pretty much steady considering it's a t5ho, straight bulb system. lumens will be somewhat comparable... and it's not uncommon for lower lumens bulbs to produce better or comparable par. better bulbs are better bulbs, not necessarily brighter looking or more expensive.

ime/imo... the light the op is asking about is plenty to grow the plant the op is asking for at the depth the op is asking about. i can say that much. but i think it might be a bit tough without co2... especially for a carpet.

 

[GoldLenny]

At 1.5-2 wpg of T5 lighting you should be able to grow most plants. That's all you need to know.

Not if the bulbs are 1,000K or 50,000K rated.

In the OP's original post, they listed one of the bulbs at 6,700K (good) and the other at only 1,000K (not so good, unless they meant to type 10,000K, which would be much, much better than 1,000K)... so you can't just go by WPG. It's simply a useless POS standard to go by with all of the lighting options available today... and without knowing more about the light bulbs being used.

If they in fact have only one good bulb, then they're not getting the lighting they might think they are getting if they only use WPG as the standard.

 

[dundadundun]

didn't see those posts... pappy's got a point.

 

[rockhoe14er]

wow nice info guys thanks. Yeah i made a typo it should have been 10,000 k light not 1000

 

[GoldLenny]

wow nice info guys thanks. Yeah i made a typo it should have been 10,000 k light not 1000

I'm glad you caught my question about that potential typo with all the other stuff that was posted. In that case, your Kelvin ratings are at least in a good range for plants. When it's time to replace your bulbs, at least you know you can compare the lumen ratings and keep the Kelvin ratings around 6,500K but as high as 10,000K is OK if the price is right. If there are two bulbs with the same wattage and similar Kelvin ratings, compare the lumen output and if one of them has a much higher lumen output level, seriously consider it if the prices are comparable and the lifetime ratings are also comparable. If one bulb has a much longer expected lifetime and the price is either lower or a little higher, that would give some weight to that bulb.