Comparison of Lighting Types (Lumens and Watts)

[newt]

Four sites and thousands of posts later>>>>>>Finally I run in to some one who understands.

[BlueRam]

Originally Posted by newt

Why discuss lumens for their effectiveness on aquarium plants? Lumens is meaningless for plants. Plants do not utilize green light for photosynthesis. A higher lumen rating at the same wattage often means greener light. Lumen is a rating weighted entirely towards human perception. It has little to do with the value of a light for either growing or viewing plants.

Agreed. The utility of comparing Lumens in the context of the above post is that the number is generally printed on the bulb or easy to find. So if the question is how much better is Brand X T12 at Y color from Brand X T8 at Y color and if the assumption that the specturm is close enough holds, we can say that in terms of OUTPUT T5>T8>T12. This is important for the person who thinks a 40W T12 is 25% brighter than a 32 W T8!

Where I get into serious trouble is the comparison of incandescent, fluorescent, and halide technologies. The Lumen number just does not fully capture the output and does not serve as a decent comparison.

I would be more than happy to retest various light combos with a power meter. All I need is the hardware

[defdac]

I would be more than happy to retest various light combos with a power meter. All I need is the hardware

No all you need is the spectral distribution, the watt and the lumens output - and some funky math as shown in the Ivo Busko page at Aquabotanic. I've made a calculator for it, and have some values calculated here:
DefBlog - PUR-efficiency list

[BlueRam]

Originally Posted by defdac

No all you need is the spectral distribution, the watt and the lumens output - and some funky math as shown in the Ivo Busko page at Aquabotanic. I've made a calculator for it, and have some values calculated here:
DefBlog - PUR-efficiency list

Thanks for the link. I added it to the original article. The Ivo Busko article answers the next logical question as to what PARTICULAR bulb and therefore outside the scope here. Please PM me if you would like to see portions of the original article modified.

[spwbedford]

I would like to say thanks on how helpful these posts have been. Question, what would be the effects of using a megnetic ballast with starter with T5HO tubes?

[BlueRam]

Originally Posted by spwbedford

I would like to say thanks on how helpful these posts have been. Question, what would be the effects of using a magnetic ballast with starter with T5HO tubes?

While the bulb may light, the idea behind T5 is to use electronic ballasts to the fullest to maximize output for a given current consumption.

"The T5 lamp is currently designed for operation only on high-frequency, rapid-start, or programmed rapid-start electronic ballasts."

http://www.pnm.com/customers/tech_guides/PA_11.html "How to Make the Best Choice"

A Workhorse or other T5 ballast is rather easy to find. (the endcaps and bulb length are also different)

[waterfaller1]

Good thread.

[Hilde]

I found this link to calculate light need here. Anybody else use it?

[plantbrain]

Originally Posted by Hilde

I found this link to calculate light need here. Anybody else use it?

I think it's as useless as the prior post suggest here in this thread.
It does not measure what the plant's are receiving, you need a meter to measure that and to fairly compare light from one tank to another.
It's a good attempt however. But nothing beats measuring the plants and in the tank in question.

This also gets around brand names, reflectors, smugdes on glas,s lids or not, differing plant heights, corners, uneven lighting(bright in some places, not so bright in others) etc.........

PAR meters are relative cost effective and the data is more useful.
You may share or perhaps even rent one from another member etc, then adjust the light to where you want it.

Apogee makes a cheaper version and they are about as good as LiCOR's.
A few clubs bought one to share amongst their membership(not a bad way to go).

I honestly have never had issues with the W/gal rules, but the light has become more efficient so I've gone to lower and lower light watts over the years.

So what was once 2-3 W/gal, might be 1 or 1.5w/gal today.
A meter gets around that issue also.


Regards,
Tom Barr

[guppygolucky]

I have a 20gal tank...not an extra high or long. the hood is an eclipse 2 with 2 bulbs (18inches) that came with the hood T8-15Watts. I changed one bulb to a Plant and Aquarium (by Philips) 15Watt with 410 Lumens with a color temp of 2700K. The other bulb is a Natural Sunshine (by Philips) 15Watt with 590 Lumens and color temp of 5000K and color rending of 92.
My substrate is fluorite. i have anacharis, anubias nana, and a microsword.
Is my lighting sufficient? also if not...where do i find a local retailer that sells a higher wattage bulb.
my other question is when 6500 Kelvin is recommended...is it per bulb or combined?
Thanks for your help

[Church]

Kelvin ratings don't "combine." If you have 2 x 6500k bulbs in there, your lighting is still 6500k, not 13000k. That being said, yes I highly recommend you keep within the range of 6500k to 10,000k. Your 5000k bulb is close so that one may be okay (albeit a little too yellow for my liking), but I think that 2700k one needs to go. That's the spectrum you would use if you were growing fruits and/or flowers in a terrestrial garden.

I don't know much about the Eclipse tanks, much less their hoods, but I do think that 30w will be sufficient in a 20g tank, to be able to grow low light plants anyway. But you should make sure they are in the right spectrum. Pay little-to-no attention to marketing gimmicks that claim certain bulbs to be "for aquariums" or "just like sunlight" or whatever. Just simply go out there and grab some 6500k T8 15w bulbs. I personally tend to like blending 6500k and 10,000k in my tanks. It makes for a very crisp, white light, that is neither too blue or too yellow.

But this is just my opinion of course.

[guppygolucky]

ok. Thanks so much! I will change the bulbs from your recommendation. a 6500K and a 10000K bulb. So when i am looking at the watts per gallon. im only pushing 1.5 WPG. will that be enough?
Just for my own enlightenment. If the WPG is not really a concern...and only the K is concerned, what happens with a larger or a deeper tank?
Thanks for your time

[lauraleellbp]

Kelvin rating only refers to the color of the light coming from the bulb and has little to do with anything other than aesthetics when it comes to a FW planted tank.

I know there's quite a bit of discussion of Actinic light, coral photosynthesis, and water penetration over in the SW hobby, but that's not really applicable to the FW side.

[Church]

Originally Posted by guppygolucky

If the WPG is not really a concern...and only the K is concerned

These are both untrue statements, so don't get confused again. Wattage is still a concern but WPG is not really the best way to look at things. It's just a generic guideline people use for lack of anything better. And saying that only the K is concerned is also very false, because even if you have the correct spectrum, what does it matter if the light doesn't reach the plants because it's too low of a wattage?

[Kisho3]

:] Wow. So the higher the K the brighter it is to one's eyes. I found my answer thanks a lot!