# PAR/LED Lamp Comparison



## Big Dog (Nov 4, 2009)

How do you like the Finnex Ray II Ultra Slim LED ?


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## jonnyboy (Mar 13, 2013)

I have on on my 20gal and I do like it, but I didn't do enough research before buying it. I was kinda going for low tech...so I'm at medium light now with one screen over the lamp to help reduce it's par.
Overall it's a great light! Doesn't get too too hot, brings out great color in everything, and it's super small!


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## jonnyboy (Mar 13, 2013)

acitydweller said:


> With my Hoppy PAR meter in hand, a series of tests were conducted on a 10 gallon Aqueon tank at the lamp, mid tank (+6") and on substrate (+11").
> 
> The fixtures and specs:
> 
> ...


When you say 'mesh' what do you mean? I'm using plastic window screen.


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## acitydweller (Dec 28, 2011)

yes, and thanks for pointing it out. I used the fiberglass version as it was excess from my window project. Apologies for the inconsistency in terms referenced. It will be corrected shortly. 

Just some observations. The Ray 2 can easily be brought down to the fugeray level of performance. Personally im waiting for a mfr to create a rgb/ray2 equivalent fixture...

Other factors to consider. Tank height...on a lower profile tank like a deep blue 5 partition aquarium with a 7" tank height, all of the fixtures including the Fugeray will be in the medium to high light territory and require elevation. The height of the tank should always be factored into the equation as the light spread, intensity and color temperature may encourage Algae while requiring higher doses of co2. 

My high tech setup uses a RAY II and MonsterRay in tandem along with mild co2, less than 1bps. The addition of the monsterRay was not to promote faster growth but rather to supplement the color spectrum which was omitted by the RAY II. The additional lamp has coaxed all the colors to grow out of each of the plants which is visible even when the plant is removed from the tank. This is nothing short of amazing and likely appreciated by any hobbyist seeing their plants do so well. The feeling reminded me of when i first started dosing my tanks and had all my plants perk up.

I had conducted some tests with a custom LED fixture using only Red then Blue light on alternating days. Now i have a grow lamp with dedicated blue and red LEDs constructed in a Flood light profile bulb (which is deceiptively heavy) to test on some HC and dwarf hairgrass. The hobby just got a lot more interesting!


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## Hoppy (Dec 24, 2005)

It looks like the screen drops the PAR by about 40% per layer, just as it does with fluorescent lights. Good news! Thank you for doing the test.


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## chibikaie (Aug 2, 2012)

Wow, I hadn't realized the PAR dropped that much with distance. I would love to see the results on the Fugeray when you get it.


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## somewhatshocked (Aug 8, 2011)

I'd be interested in seeing results with a better meter.

With my Ray II at 11" from the substrate, I get about 80 PAR. With a single layer of fiberglass window screen, I get PAR in the neighborhood of 65.

My Current + fixture at 11" is 35.

Either your meter is way off or it's one of those homemade ones that are off by 20-30 with conversion or what have you.


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## rcs0926 (Jun 14, 2013)

somewhatshocked said:


> I'd be interested in seeing results with a better meter.
> 
> With my Ray II at 11" from the substrate, I get about 80 PAR. With a single layer of fiberglass window screen, I get PAR in the neighborhood of 65.
> 
> ...


I have to agree that something is a little off with the numbers. They don't quite jive with samamorgan's "LED Lighting Compendiumm" thread and Hoppy's "Lighting an Aquarium with PAR instead of Watts". Both those threads show that PAR at 12" is in the mid-high 70 range. Finnex's official PAR Data shows 74 PAR at 12". 

However, regardless of the numbers shown in the OP, it does appear that one layer of fiberglass window screening does reduce PAR by 40%. It would just be nice to know which PAR values are correct because based on the numbers provided by Hoppy, samamorgan and Finnex (official PAR values), I only need one layer of window screening. However, based on acitydweller's numbers, I don't need any window screening at all, which I'm pretty sure is inaccurate.


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## somewhatshocked (Aug 8, 2011)

I don't see 40% drops when using LEDs and window screen. Definitely see it with standard bulbs, though. Usually takes me a couple layers of screen to get 40-50% dampening.

In part because LEDs are so small compared to traditional bulbs.


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## saiko (Mar 30, 2007)

I will be interested to know if there is/should be lesser screening from glass compared to acrlyic.


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## jonnyboy (Mar 13, 2013)

I would think acrylic would screen the lighting less than glasses because its more transparent?


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## jeffkrol (Jun 5, 2013)

jonnyboy said:


> I would think acrylic would screen the lighting less than glasses because its more transparent?


First it would depend on the type of "plastic".. As a reference from the greenhouse industry (I'd have to check, but the "polycarbonate" they would likely be using is multi-walled and not really "glass clear"..:
Point is glass or plastic has probably no discernible difference and if anything plastic is less "clear"..to certain wavelengths..










Re: other than polycarbonate:


> Colorless ACRYLITE® acrylic sheet typically absorbs less than 0.5% of visible light per inch of thickness. However, some light is reflected at both surfaces. A beam of light striking a smooth ACRYLITE sheet perpendicular to the surface (at 0° angle of incidence) will lose approximately 4% of its light at each surface due to reflection, resulting in a total loss of 8%. Therefore, the overall light transmission will be approximately 92%. If light rays strike the sheet at angles greater than 30° from the vertical, the
> surface reflectance will be greater than 4% and the overall transmission will be smaller. For example, when light falls on colorless ACRYLITE GP or ACRYLITE FF sheet from all angles, as from a sky of uniform brightness, the transmission factor will be approximately 85%.


http://www.tapplastics.com/uploads/pdf/acrylite light transmission.pdf

PDF Chart (pg 7) matches above for polycarbonate @ 400-1100nm slightly more than 90% transmission.


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## somewhatshocked (Aug 8, 2011)

This is a topic that comes up on a regular basis here on the forum.

Using glass/acrylic tank covers - even when a little dirty or scratched - has little impact on lighting.


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## jeffkrol (Jun 5, 2013)

somewhatshocked said:


> This is a topic that comes up on a regular basis here on the forum.
> 
> Using glass/acrylic tank covers - even when a little dirty or scratched - has little impact on lighting.


I need to learn how to be brief..........


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## MichaelKelley (Jun 24, 2013)

I do not understand much about this comparison, but all I can say that I like the LED and they are the best in my opinion. I am using led for my aquarium and I feel quite comfortable and the electricity bill is also very less.


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