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  #426  
Old 12/06/2007, 07:22 PM
TheBishop TheBishop is offline
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Were each of these measurements taken from directly under the bulb (i.e. the hotspot for each reflector)?
  #427  
Old 12/06/2007, 09:47 PM
JRaquatics JRaquatics is offline
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The hot spot of the reflector is no directly under the reflector. All mine hotspots are on on an center ring of the reflector more so on the left side with the Reeflux bulbs nipple faced up.
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180 Gal Reefready, 75 gal Sump/Fuge, Reeflo 200 skimmer, 3 250 Reeflux Bulbs in Lumen Bright reflectors powered by coralvue electronic ballasts, PM Kalk reactor, 2 Vortechs, Geo 618 calcium reactor
  #428  
Old 12/06/2007, 10:29 PM
bubbletip2 bubbletip2 is offline
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Something I noticed lately as well Jeremy - at least on a 12K Reeflux. When the nipple is up there is a bar that splits the "hot spot" on both sides of the bulb. It seems the left side on both my bulbs as well as yours are usually a bit hotter.

The Bishop,
We tested under the bulb, 6", 9", etc. I am not sure if we were directly under the bulb or an inch to the left or right - all measurements under the bulb in a 2" radius were in the high 500's for the LumenBright and high 200's and low 300's on the LumenArc. Hopefuly that helps.
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  #429  
Old 12/07/2007, 07:08 PM
DaveIrks DaveIrks is offline
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re-test

Quote:
Originally posted by bubbletip2

So in order to single out the reflector we used the same 400w PFO Magnetic ballast and the same 400w XM 20K bulb. Here we go folks... Thanks again Justin for helping to verify the real deal between these two reflectors.

After looking at your numbers, that looked "interesting" to say the least, we decided to do the same test. Here are the results (with pictures). Both were done on the same 400W bulb and electronic ballast. Both reflectors were level +/- 1/16" (I'm only human). Both tests were done with the center of the bulb 20" from the testing surface (following your 21"-1" test, since we don't have the necessary water tank to do the 3" under test). The light meters are about +/- 5% accuracy depending on battery life and heat. The Lumen Bright was purchased from Custom Aquatic, the Lumenarc 3 was purchased from Lumenarc Lighting.
The most interesting note is when we did our test, the difference between 0" under and the LB and 18" out, is roughly 95% light loss (pic:LB0and18), vs. your test, which showed only a 75% light loss. The lumenarc lost 80% of it's light to this similar point, where your test showed only a 50% loss. I'm puzzled as to what could cause a discrepancy this big. Was your meter level when you took your readings?
I also included some points you may have missed, the diagonal points. To cover a 2X2 area, you need to go 18" diagonal to cover the corners. I have included 9"X9" (13" away) and 12"X12" (18" away), where the lumenarc's spread pulls away.

..... LB LA3
0" 632 380
3" 597 375
6" 501 328
9" 340 252
12" 173 175
15" 74 116
18" 33 76
9X9" 105 191
12X12" 41 107
The LA3 is 250% brighter at the 2'X2' corner.
(pic:LA12diag vs. LB9and12diag)

And here are the pictures:




  #430  
Old 12/07/2007, 07:48 PM
TheBishop TheBishop is offline
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I'm not sure I'm following the numbers presented here.
Do the numbers (in inches) represent a changing height of the bulb above the sensor or does it represent lateral movement of the sensor with the bulb remaining at a consistent height?

Bubbletip- Same question regarding your numbers. I get the impression that DaveIrks was moving the sensor laterally and Bubbletip was adjusting the bulb up and down...or am I confused?
  #431  
Old 12/07/2007, 08:46 PM
rishma rishma is offline
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As cool as it is to see the numbers from tanks, methods like DaveIrks are highly credible.
  #432  
Old 12/07/2007, 09:55 PM
bubbletip2 bubbletip2 is offline
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Quote:
Originally posted by TheBishop
I'm not sure I'm following the numbers presented here.
Do the numbers (in inches) represent a changing height of the bulb above the sensor or does it represent lateral movement of the sensor with the bulb remaining at a consistent height?

Bubbletip- Same question regarding your numbers. I get the impression that DaveIrks was moving the sensor laterally and Bubbletip was adjusting the bulb up and down...or am I confused?
The testing Justin and I performed was in no way a laboratory testing environment. Justin happened to be working in the LFS where we did this and needed to take care of customers as they came in.

Justin and I agreed that to just show the numbers as we gave at different lengths from the bulb either on the surface and somewhat breaking the surface would be all we need to show a clear difference between the reflectors. Each reflector was placed so the bulb sat 21" from the surface of the water. No change in height at all. All horizontal measurements on the same line.

If you look at the numbers of the line "LB 1" Above" and follow that line across, that will give you an idea of where on the frag tank the sensor was placed. Now was it at the exact same spot each and every time with each reflector. Probably not however each measurement was done right under the bulb, 6" away, 9" away, 12" away, etc. Even in the event that the placement was slightly off, we are really talking baout 5-20PAR so not really a big deal. Like I said, we were simply trying to show the values under each reflector at each length from the bulb 1" above the surface and 3" below the water. In my opinion the numbers speak for themselves.

I and others on here have posted several photos with PAR values in this thread and the question of credibility has all of a sudden popped up I am doing this testing to simply show the differences amongst the reflectors to help reefkeepers make their own decisions.

Back to measuring...

David Irks,

Can you tell us what type of light meter you are using - looks like a footcandle meter? Also, what brand bulb and ballast are you running? I don't know myself what is an equivalent way to measure PAR from a lux meter or footcandle meter. Justin and I actually tested the conversion equation people have been passing out against the Apogee and the numbers were off dramatically Justin immediately disregarded anything the Lux meter showed in regards to PAR. We could have broke the Lux meter out at the store when we tested but really did not feel the need as the Apogee would give us accurate PAR readings and it is pretty much what everyone on this thread has used for testing so far.

I know Lux meters are specific to 555nm - basically green light and have little to show in other areas of the spectrum. Even an Apogee underrates bulbs by 8% that have a blue spectrum so theoretically our PAR values would actually be higher.
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  #433  
Old 12/07/2007, 10:02 PM
bubbletip2 bubbletip2 is offline
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Quote:
Originally posted by rishma
As cool as it is to see the numbers from tanks, methods like DaveIrks are highly credible.
Please don't take any offense, but I feel tests done of bulbs in the air relate very little to what we are trying to accomplish in our tanks. There is no coral in sight, no water, and no organics in that water to dilute the light provided. I am much more interested in light values within the water column as everything changes when you break the surface. I only test surface values as a reference point to compare to other bulbs. If you notice the light drops quickly even right under the bulb as soon as you get below the surface of the water.
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  #434  
Old 12/07/2007, 10:23 PM
TheBishop TheBishop is offline
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Bubbletip- Thanks for the clarification. In no way did I intend to suggest that your numbers weren't credible. I just didn't understand whether you were moving the sensor laterally under the reflector or moving the reflector up with the sensor stationary.

Your explanation cleared it up.
  #435  
Old 12/07/2007, 10:27 PM
Deuce67 Deuce67 is offline
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I dunno man. Im a little suspicious of someones test who has all of 9 post that all involves something about Lumenarcs. Not saying it isnt legit but a little suspicious
  #436  
Old 12/07/2007, 11:02 PM
rishma rishma is offline
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Quote:
Please don't take any offense, but I feel tests done of bulbs in the air relate very little to what we are trying to accomplish in our tanks. There is no coral in sight, no water, and no organics in that water to dilute the light provided. I am much more interested in light values within the water column as everything changes when you break the surface. I only test surface values as a reference point to compare to other bulbs. If you notice the light drops quickly even right under the bulb as soon as you get below the surface of the water.
No offense, just a difference of opinion. I think both test methods have value and I am glad to see numbers in real tanks with water, coral, fish and rock. They are very helpful, as are just plain nice pictures.

All the variability you note above (organics, refraction at the surface, etc) is exactly why there is so much value in data collection in a controlled environment with air only. The more variables you eliminiate, the better you can answer the real question (that interestes me) - what does the spread and intensity of this reflector look and how well will it illuminate my tank?

I realize that the PAR values at a the coral in my tank are not predictable based on an air only test (not to mention bulb/ballast variability); however, you get a very clear idea of the uniformity and intensity of light incident at a given point from the bulb. This is very useful because the behavior of light once it enters the water surface is reasonably predictable and consitent. Understanding how the light behaves leaving the reflector is the real trick.

You are correct that the light values in the water column of MY tank is what I should be really interested in. Clearly the best way to choose would be for everyone would be to buy several reflectors and hang them over their tank and take measurements at all the various points of interest. I am not inclined to do this, so controlled grid measurements in air only are very valuable because they eliminate the inherent variability of tank tests. If, as you say, air tests relate very little to what we are trying to accomplish in our tanks, then one could certainly argue that values from your tank with your bulbs, balast, water, rock, etc are of little value for me and my tank. I do not think either of these arguments are true.

As for the # of posts that DaveIrk has, it is not of much consequence provided he chooses to continue with this discussion. Please be welcoming and hopefully he will us all learn a little more about these reflectors. In God we trust, everyone else must bring data.

Cheers
  #437  
Old 12/07/2007, 11:14 PM
rishma rishma is offline
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Quote:
I and others on here have posted several photos with PAR values in this thread and the question of credibility has all of a sudden popped up I am doing this testing to simply show the differences amongst the reflectors to help reefkeepers make their own decisions.
I missed this the first time. It looks like you took offense. Really, none intended. As i noted above, both methods have value and I appreciate the numbers you are posting. I was not questioning personal credibility but tank numbers are going to be inherently more variable than a grid in air. We can argue about the merits or value of one set of measurements but certainly a grid in air is more repeatable.
  #438  
Old 12/08/2007, 11:09 AM
bubbletip2 bubbletip2 is offline
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No offense taken rishma. And like you said just a difference of opinion. If you can agree to disagree, I feel an open air test will not tell you much about illuminating your tank as each reflector drives light into the water differently. I actually tested a parabolic relfector yesterday and was getting 100-150 on the bottom under a 400w bulb along with 2 -250's next to it and 3-6ft VHO's. Clearly the reflector did not drive light deep into the tank. Every tank I had tested so far has raised an eyebrow of the tank owner when they actually see what their reflectors are actually putting out or their VHO's or magnetic ballasts for some reason. Every tank other than a LumenBright tank I should say

Again I will not argue that a grid is more repeatable. Just to note, when we rechecked certain numbers, it was interesting that the second set was very close to the first, maybe 1 or 2 PAR off. So at least on the same tank the numbers are repeatable. Another thing to note, if you look at Deuce's, Kurts Reef's, Mike L.'s(Acropora Nut's), and my tank, we all have 400w 12K Reeflux and are pretty much measuring comparable numbers so I believe anyone using this bulb, ballast, reflector combination can get a pretty good idea from the pictures already posted. Again, an open air test will never tell "you" how the light will be driven into "your" tank. Everything changes when the surface of the water is broken and some reflectors drive light through the water better than others. It does not matter how far a distance you place the bulb from a grid, without water you will never know how that light will penetrate "your" water.

The last few weeks have been very interesting owning a Apogee meter. I have opened a lot of eyes as to realizing their thoughts on how their lighting systems were performing was way off. Justin had measured his 30g long T5 tank and noticed his LUX meter was showing numbers almost in half of what the PAR meter was showing. Following the results from the LUX meter he decided to lower his T5 fixture because he did not think he had enough light. He was very surprised as was I with the "actual" results and realized his fixture did not need to be so low.

I suggest to anyone if you have the means to purchase one(an Apogee Quantum Meter) for yourself or borrow one from your local reef club or suggest that they purchase one to be shared amongst club members. I don't suggest relying on everyone else's data to determine what could be a detrimental factor in the life of your inhabitants in your reef tank. Many of our tanks costs thousands of dollars and I feel a couple hundred dollars is a drop in the bucket to have some certainty in regards to your lighting. Honestly, it has been the best investment I have made in reefkeeping in a long time and I have gotten a lot more use of it than I thought I would, including fellow reefkeepers that are no longer in the dark about their tanks
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  #439  
Old 12/08/2007, 11:12 AM
JRaquatics JRaquatics is offline
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Everyone has to understand Jim is a hobbiest just trying to gather information on lighting for his his own amusment and is kind enough to share his findings. I can't say this for everyone who post here because I don't know them or their intentions may be.
So everyone has to take these test for what they are worth, and this should pertain to almost everything on this forum.
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Last edited by JRaquatics; 12/08/2007 at 11:21 AM.
  #440  
Old 12/08/2007, 01:12 PM
fijiblue fijiblue is offline
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I think the variance could be a lot of things.

1). Water movement on surface vs no water at all.
2). Jim & Justin used magnetic ballast vs electronic ballast??
3). The meters used were different as well.

I agree there is no conversion from LUX to PAR. I once used a conversion (Lux x .0111 + 1.53) only to find it was way off! A closer conversion would be (Lux x .0111 x 1.67). Even then, this only works out of the water. Any measurments under the water cannot be converted accuratley in my opinion.

Nice job, guys!
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  #441  
Old 12/09/2007, 10:41 PM
grandp10 grandp10 is offline
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Quote:
Originally posted by bubbletip2
Here is a shot with a black background - it is under 400w however.

Why is the par more under one of the lights?
  #442  
Old 12/09/2007, 10:41 PM
grandp10 grandp10 is offline
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Quote:
Originally posted by bubbletip2
Here is a shot with a black background - it is under 400w however.

Why is the par more under one of the lights?
  #443  
Old 12/09/2007, 10:42 PM
grandp10 grandp10 is offline
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Sorry about the double post.
  #444  
Old 12/10/2007, 10:15 AM
glxtrix glxtrix is offline
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you'll pretty much always have PAR value shift from lights due to age of bulbs, burn method or manufacture date. Just because you buy bulbs at the same time, doesnt mean the age is going to be the same.
  #445  
Old 12/10/2007, 11:23 AM
bubbletip2 bubbletip2 is offline
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Quote:
Originally posted by grandp10
Why is the par more under one of the lights?
How's it going?

I had gotten some used 12K Reeflux and we could not tell if they were the 1 month old bulbs or the 4 month old bulbs. After measuring I figured the one on the left was a 4 month old bulb as I put two new one's on a couple weeks ago and both are measuring over 1400 1" above the surface. This test was done 2 months after I fired up the bulbs.

I am actually currently testing the life of a 12K Reeflux by measuring each bulb 1x week to see how much they decline over time. After 6-8 months I will post the data.
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  #446  
Old 12/10/2007, 01:27 PM
jnarowe jnarowe is offline
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interesting results. So it appears that the LB is brighter in a sense because the light is more focused, but the spread is smaller right? So these could be employed on deeper tanks to get the penetration/PAR needed down low correct? But they you would need more of them to get the spread, or do like I do and run them on movers.
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  #447  
Old 12/10/2007, 03:46 PM
grundig5 grundig5 is offline
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I've got a 36x18x25deep tank with eurobracing, and after reading this thread it would seem the Lumenbright would be the best reflector if I were to use 2 of them close together. To go with a single reflector, the LA would be the better option. Does that sound about right?
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  #448  
Old 12/10/2007, 06:24 PM
grandp10 grandp10 is offline
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Thanks for the info bubbletip2.
  #449  
Old 12/11/2007, 08:51 PM
grandp10 grandp10 is offline
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Went ahead and placed an order for the Lumen Bright minis/ Reeflux 12k combo from Reef Specialty. Great service and prices and even fast shipment. Really informative and very nice guy to deal with. Easily one of the best places I have ordered from. Also thanks to the others for all the great info on this thread.
  #450  
Old 12/12/2007, 02:21 AM
ganjero ganjero is offline
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so according to these numbers the lumen bright is really much better than the LAIII? Is it worth geeting 2 big ones for a 100g tank or should I go with minis?

BTW is lumen bright the same as lumenbrite III?

Last edited by ganjero; 12/12/2007 at 02:36 AM.
 

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