# finnex ray 2 on 75 gallon



## jgc (Jul 6, 2005)

I can not address a 75 gallon directly, but I have a 58 show - which is a 75 cut down to 3 ft.

My 250watt metal halide was failing so I rushed this experiment (it will run about 10 minutes and then turn off for about the same). Took pictures with the Ray 2, a shop light 2xodno, and my 250 watt. Brightness wise the 250watt is much brighter - but then again it is 250watts (versus 100, and 28). I think the ray 2 was brighter than the odno - but my camera's exif data does not show a material difference (the odno has more spill, so that may have caused the camera data to be skewed).

Since I only went to the ray 2 this weekend - I have no experience to how the plants will enjoy it or not - I have had significant deterioration over the last 2 weeks as the hqi failed.
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Please understand, I am bias as I have always tried to keep more than 200 watts on top of my 3 ft tank. I think I was in the HIGH light level, and have probably fallen to medium to medium-high. I will edit this post once I post pictures on my tanks blog.
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Ray II









2x ODNO Shoplight









250watt HQI









Please note that these are iphone pictures with auto exposure on. To keep perspective, the first 2 have 1/20 second exposure times - the third is 1/129 second.


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## nvladik (Jan 12, 2012)

I am using one, here's a shot of it before it was filled.


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## Hoppy (Dec 24, 2005)

The data in http://www.plantedtank.net/forums/showthread.php?t=189944 show that you would get medium light, around 45-50 micromols of PAR, with that light on a standard 75 gallon tank. Last week I measured the PAR from a 16 inch long RayII light, and the readings were very close to what is in that thread, including the spread of the light. I think those are superb lights for getting good uniform light over a very large area. And, don't forget some light will be reflected off the front and back glass down to the substrate, so you should get even more PAR than the data show.


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## scotty82 (May 9, 2012)

Perfect. Thanks to both of you for your input. Being in the medium light level is what I'm tying to be in. Still great light and matches my diy co2 quite well. Know I know what I'm going to ask the wife for Christmas.


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## Hoppy (Dec 24, 2005)

scotty82 said:


> Now I know what I'm going to ask the wife for Christmas.


Show your wife what a great guy you are by offering to let her buy what she wants for Christmas, and, of course you will relieve her of the worry of finding something you will like, by buying what you want for Christmas.:redface: This has worked extremely well for me.


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## BriDroid (Oct 7, 2012)

scotty82 said:


> ...now I know what I'm going to ask the wife for Christmas.


Same here, I'm getting one for my 72 bow front (almost same dimensions as your 75, but with a curved front). From all the research I've done on here and Google, it seems like it's the way to go!


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## houseofcards (Mar 21, 2009)

Aren't those readings based on a tank without water?


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## Oxl (Oct 21, 2011)

I've been eyeing that light fixture, nice thing about it is that it is so narrow that it would be simple to add more units if one proves to be insufficient.


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## scotty82 (May 9, 2012)

Hoppy said:


> Show your wife what a great guy you are by offering to let her buy what she wants for Christmas, and, of course you will relieve her of the worry of finding something you will like, by buying what you want for Christmas.:redface: This has worked extremely well for me.


I wish it was that easy. I tried that 2 years ago and she said it's not fun doing it that way. But after last year I think I'll try it again and say "see this way we wont spend money on anything to just sit in the closet and collect dust."

I'm sold on the ray 2 thought. The only thing is I wish it had 4-6 "moonlights" for night time.


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## scotty82 (May 9, 2012)

houseofcards said:


> Aren't those readings based on a tank without water?


Yes, but from what I've read about the values they don't seem to drop much at all going through water. Well not at least just 20" or so of water.


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## Kai808 (Jul 19, 2011)

How about an early Christmas gift? Check out the Black Friday deals. 

http://www.plantedtank.net/forums/showthread.php?t=197885


http://www.aquavibrant.com/index.php/specials.html


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## scotty82 (May 9, 2012)

Kai808 said:


> How about an early Christmas gift? Check out the Black Friday deals.
> 
> http://www.plantedtank.net/forums/showthread.php?t=197885
> 
> ...



Yes!!! I will be one of the guys that gets up at 1am to get one of those.


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## Hoppy (Dec 24, 2005)

houseofcards said:


> Aren't those readings based on a tank without water?


I did some experimenting back when I first got to use a PAR meter. I found that the intensity with water is a bit higher than without water. Eventually I figured out that the air to water interface acts to slightly focus the light, increasing the intensity, plus, for most tanks, you get some light reflected off the front and back glass, which also increases the intensity. After that I started just measuring PAR out in the air.

All we are doing is stating that a light which produces XX PAR at YY distance, in air, will give you low or medium or high, etc. light in a tank that has the light YY distance from the substrate. Of course in a tank of water, even with no plants, the PAR varies a lot from one location to another in the tank.


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## jgc (Jul 6, 2005)

In addition to the refraction of the light as it enters the water (essentially creating a lens), there is now a water/glass rather than an air/glass interface which I suspect reflects more light (plus that light is at a different angle when it hits the glass causing greater reflection).


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## jester56 (Oct 28, 2012)

Oxl said:


> I've been eyeing that light fixture, nice thing about it is that it is so narrow that it would be simple to add more units if one proves to be insufficient.


I have 2 36" Ray II fixtures on a 50 gal. Only drawing 29 watts for the daylight 290 LED model, these things throw an awesome amount of light. After what Hoppy said, I'm considering hanging mine from the ceiling. Radiant heat is almost non existent. I can pick one up in the center and it is barely warm. I'm a fan!


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## houseofcards (Mar 21, 2009)

Hoppy said:


> ...I found that the intensity with water is a bit higher than without water. Eventually I figured out that the air to water interface acts to slightly focus the light, increasing the intensity, plus, for most tanks, you get some light reflected off the front and back glass, which also increases the intensity. After that I started just measuring PAR out in the air.
> 
> All we are doing is stating that a light which produces XX PAR at YY distance, in air, will give you low or medium or high, etc. light in a tank that has the light YY distance from the substrate. Of course in a tank of water, even with no plants, the PAR varies a lot from one location to another in the tank.


So why do those fishes under the water develop their own light systems. What the sun doesn't have enough PAR, LOL. So at what point does water hinder light intensity rather than enhance it?


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## houseofcards (Mar 21, 2009)

jgc said:


> In addition to the refraction of the light as it enters the water (essentially creating a lens), there is now a water/glass rather than an air/glass interface which I suspect reflects more light (plus that light is at a different angle when it hits the glass causing greater reflection).


meh.. you can throw a lot of science on this, but home aquariums are not controlled science experiments. Any manufacturer will state their highest, most desirable numbers in a controlled setting, but it's really not 'real life' In the same way my car is suppose to get 40 mpg, but only get's 30. I guess the auto manufacturer forget that in real life people don't drive in wind tunnels, and they don't keep a constant speed of 50. And the biggest surprise is they actually have other people in the car too. On thing your forgetting is the tank the light goes on is not empty there will be hardscape and other plants in the way, there will be surface movement and water that isn't crystal clear like the air. Some light can also be reflected up and out or away from the plants. So give me PAR through air and an empty tank and I'll give you a Jeep that think's it's a Prius.


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## jgc (Jul 6, 2005)

agreed - everything we do is an estimation. More of an art than a science. PAR in Air gives us a good comparable baseline.

That said, I now have I week with the Ray II on my tank. While much less light than my HQI Metal Halide - I am getting much better growth with the Ray II than I expected (abet I expected to see plants gradually melting away - so any growth is much better than I expected). Lots of new shoots and leaves. Makes me more optimistic.


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## houseofcards (Mar 21, 2009)

jgc said:


> agreed - everything we do is an estimation. More of an art than a science. PAR in Air gives us a good comparable baseline.
> 
> That said, I now have I week with the Ray II on my tank. While much less light than my HQI Metal Halide - I am getting much better growth with the Ray II than I expected (abet I expected to see plants gradually melting away - so any growth is much better than I expected). Lots of new shoots and leaves. Makes me more optimistic.


Just keeping it real, but yes I agree. That's good to hear that your getting growth after the switch. What kind of plants are you growing?


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