Measuring Led Lights

[Ch4rlie]

I seem to be having a little trouble trying to understand how aquarium lights are measured, in particular LED lights.
 
Advice and recommendations would be more than welcome.
 
Recently I had purchased these LED at 3 watts per led, with the plan for a high tech 22l nano tank.
 
http/www.ebay.co.uk/itm/151171228154?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
 
Other than the 3w per LED, that is all the information i have so far. I'd like to know and learn more.
 
The more i try to find out about LED lighting, the more confused i get, there seems to be a multitude of misinformation on internet.
 
For a start there is a whole host of scales, watts per gallon, watts per litre, PAR ( Photosynthetically Available Radiation), PUR (Photosynthetically Useable Radiation) and lumens.
 
From what I have read and asked about, it seems PAR and PUR are the best methods.
 
Does anyone have any information about measuring lights and how, particularly with PAR or PUR?
 
Will i need a PAR digital light meter?
 
Recommendations and suggestions would be great. 

 

[Freedom]

For a start there is a whole host of scales, watts per gallon, watts per litre, PAR ( Photosynthetically Available Radiation), PUR (Photosynthetically Useable Radiation) and lumens.
 

You forgot some, the Kelvin - those lights say they are 6500K -  and the lumens - those lights are 720.
 
I went through the same thing when I bought my LEDs.
 
Use Google, put in the name and add PAR to your search.  Someone out there always has it posted.  I did this: beamswork green element evo PAR
and found the one you listed above.
 
You can also email the manufacturer, or go to their website and use the CONTACT US link. 

 

[Ch4rlie]

You forgot some, the Kelvin - those lights say they are 6500K -  and the lumens - those lights are 720.
 

 
Ah, quite correct, i did indeed forget about Kelvin - is that for light intensity or colours in the light spectrum?
 
Am thinking 6,500 to 7,500k is good for plant growth as many sites are saying this but not 100%, yet anything 10,000k + seems to suit marine setups best.
 
Is that accurate at all?
 
 

Use Google, put in the name and add PAR to your search.  Someone out there always has it posted.  I did this: beamswork green element evo PAR
and found the one you listed above.

 
I have tried googling about PAR and for Beamswork LED's, seems to be conflicting information from some sites and forums.
 
What I'd really like is a decent site with reliable information about PAR and what readings means etc or is this like the Holy Grail? lol
 
Might be worth e-mailing  the Beamswork manufacture and see if they can impart with any useful information. Thanks for the suggestions.
 
EDIT - btw, you said my LED are 720 Lumens, is that good or bad and what does that mean for my tank and plants? 

 

[Freedom]

 

EDIT - btw, you said my LED are 720 Lumens, is that good or bad and what does that mean for my tank and plants? 
 

I have NO idea!  I am just as confused with LED lighting!  LOL

 

[Ch4rlie]

I have NO idea!  I am just as confused with LED lighting!  LOL

 
Lol, that makes two of us 

 

[DrRob]

Right. Lets try to make this simple, although I'm not sure that's entirely possible.
 
Watts. Ignore this, it only tells you how much electricity the LED uses. (although that can give an idea of how powerful the lights should be).
 
Lumens. Ignore this, it only tells you the quantity of light emitted in the human visible spectrum.
 
Kelvin. Can be useful, but it's a generalisation. You've probably seen pictures of red and blue things on a graph on the side of tubes. This, averaged, gives the Kelvin. 6500K is generally regarded as "daylight" and much over 10,000K starts to look blue.
 
PAR/PUR, now these are useful, they tell you the quantity of light that can be used by an actual plant. However you have to remember that they're very dependent on conditions such as water depth and distance from the light source to the surface. You can get meters to measure these, and on the planted specialist forums you'll find people measuring readings at the substrate level and discussing that.

 

[Ch4rlie]

Kelvin. Can be useful, but it's a generalisation. You've probably seen pictures of red and blue things on a graph on the side of tubes. This, averaged, gives the Kelvin. 6500K is generally regarded as "daylight" and much over 10,000K starts to look blue.

 
Even though watts and Kelvin can be termed as generalisation, it still gives you an idea of what the light does produce.
 
6,500K as Daylight, and 10,000K as blue, am taking this as a guide that daylight being better for plant growth and making the tropical tank look more natural whilst blue is aimed at corals/marine.
 

PAR/PUR, now these are useful, they tell you the quantity of light that can be used by an actual plant. However you have to remember that they're very dependent on conditions such as water depth and distance from the light source to the surface. You can get meters to measure these, and on the planted specialist forums you'll find people measuring readings at the substrate level and discussing that.

 
I have had a look at a couple of sites and forums about PAR/PUR and have seen pictures of tanks with PAR readings taken at different depths as well as different area of tank, however am still no closer to see what are good number and bad numbers, what to look for and what to avoid and also the difference between PAR and PUR etc.
 
A aquarium par meter such as these on this website
http/www.apogeeinstruments.co.uk/aquarium-par-meters/
 
But am having a hard time finding meters such as these for sale on any website. Recommendations?
 
 

Right. Lets try to make this simple, although I'm not sure that's entirely possible.

 
Now i know what you mean! Thank you for your help so far.
 
EDIT - have just found a par meter on a well known website, £200, not cheap!
 
http/www.ebay.co.uk/itm/Quantum-PAR-light-meter-/281295800567?pt=UK_Pet_Supplies_Fish&hash=item417e8948f7

 

[Freedom]

I just can't believe that most users have to buy a meter.  I think the manufacturers should be posting the info folks need to select among their various products, and if they don't they either get bombarded with messages from folks, asking for the info, or they do not make sales.
 
AS with any hobby, there will be users who are really involved and will get the meter.  But most of us should not be required to do that!  My opinion.

 

[Ch4rlie]

I just can't believe that most users have to buy a meter.  I think the manufacturers should be posting the info folks need to select among their various products, and if they don't they either get bombarded with messages from folks, asking for the info, or they do not make sales.
 
AS with any hobby, there will be users who are really involved and will get the meter.  But most of us should not be required to do that!  My opinion.

 
Agreed, most hobbyists will not even consider getting or using a light meter of any sort to be sure what their lights measures at and whether their lights are actually any good for certain aquatic plants etc etc
 
Its the lack of information thats on the box where these lights came from that annoys me, and am having to ask advice and do quite a bit of research even just to get this far!
 
Quite correct most of us should not be required to do this but thats the way it is just now anyway! 

 

[DrRob]

OK for PAR, depending on scales, good numbers would be below 30ish micromoles for low, 30-50 for medium and high is anything above, but I'm not aware of any great consensus on the numbers. Although, to be fair, I've not really been paying attention.
 
As for the difference between PAR and PUR. PAR is essentially the amount of light at a given set of frequencies that plants and such like tend to have responsive pigments.
 
PUR is the amount at the specific peaks, but does depend on the organism in question, hence simple sensors giving you PAR not PUR.

 

[BubblesLotsOfBubbles]

Well I'm not sure if this is the thread to ask but!....since its about trying to quantify light for an aquarium...
 
I am setting up a tank. Its quite close to a window. I wonder if there is any 'rough and dirty' way I can use my photographic lightmeter to measure EV incident on the tank's glass from the window. Why? You see right now I have no idea what the incident light level would be in the terms I've seen plants described IE low light level, hight light etc
 
I realise this does not represent PAR, refraction, reflection, the level at the plant's surface etc but its got to be a guide of some sort to tell me of the natural light's significance? Otherwise I'd need to use the species as indicators in my new tank (of only 22litres) buy a range and see what fairs best?