400W Bulb Testing

Are you reading a value of 16.2 on a scale with a max range of 200k (200,000 lux)? If so, then wouldn't it be 16.2k? (16,200 lux)
 
Check this out on the meter he is using:


The lux meter, a CHY model 332, was set to the '20k' lux setting (measuring in thousands) was placed on the table centered on the lamp. All measurements were taken under the same conditions, and measurements are in thousands of lux. For example, if the reading on the meter says 5.3, actual measured lux is 5,300."

So I'm not sure 16,200 is correct. If the setting was on '20K' lux then you multiply by 1000 to get 16,200.
 
I don't think that more Lux necessarily = more Par

I don't think that more Lux necessarily = more Par

I'm not familiar with the Harker article, but--based on one of the essays on Sanjay Joshi's website, and assuming that the lux readings here are accurate--there is not necessarily a direct correlation between lux and par. For example, in Sanjay's tests of various ballasts and bulbs the 400W Radium 20K bulb on either the Blueline electronic or PFO HQI ballast produced MORE par than the Ushio 400W 10K bulb, no matter what ballast was used for the latter. So in this case at least, more lux does not = more PAR.

Furthermore, in my experience at least very few sps turn brown under 400W Radium bulbs, and those that do likely do so for reasons other than lighting and eventually regain their original color (assuming that color was not the result of bleaching), or something very close to it.

How long a given bulb lasts on a given ballast is another issue, of course, but imo it is important not to make any blanket assertions about a particular bulb in the absence (or in the face) of verifiable testing.

George
 
Here's the article

http://www.animalnetwork.com/fish2/aqfm/1998/june/product/default.asp

I would have to say that yes there is a correlation between Lux and PAR. Not in every case and the equation is not perfectly accurate, but with the bulbs he used and the results he came up with I do see a pretty descent slope.

prodfig1.gif


THe equation isn't going to give you exact amount of PAR and no one should use it to document PAR. This is just what Harker found out; That there is a correlation between Par and Lux, at least with bulbs meant for this hobby with wavelengths in the right places. A higher Lux reading generally equals higher PAR reading. This makes sense.

From Sanjay's article

"Photosynthetic available radiation (PAR) is defined to be the radiation in the 400 nm to 700 nm waveband."

From other various sources like the dictionary

Radiant energy is energy given out or transmitted by radiation

Lux is the measure of Illuminance; which is the density of luminous flux incident at a point on the surface.

Amount of light is measured in Lumens

It is generally true that bulbs rated with higher Lux as well as Lumens are brighter. If a bulb produces more light at a greater density (are "Brighter") in the right spectrum (such as the bulbs meant for this hobby) then it will in turn have more radiant energy and therefore have more PAR, that is as long as it's radiation is in the 400 nm to 700 nm waveband.

At least this is what I get out of all of this lighting talk. I'm not schooled in the physics of light or anything. THis is just what I have read and what I think I know :).
 
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Sanjay's Readings

Sanjay's Readings

Here are the readings from Sanjay's article at

http://www.personal.psu.edu/faculty/s/b/sbj4/aquarium/ballast comparison/ballast-comparison.html

Ushio 400W

99.11 PPFD on a Magnetec Ballast
105.7 PPFD on a PFO HQI Ballast
107.5 PPFD on a Blueline Electronic Ballast

Radium 400W

90.63 on a Magnetec Ballast
110.2 on a PFO HQI Ballast
114.4 on a Blueline Electronic Ballast

Since the lux readings at the top of this thread show the Ushio bulb with a much greater lux reading than the Radium bulb and Sanjay's readings show that the Radium has a bit more PPFD on both the HQI and Blueline ballasts, I assume that the correlation between lux and par is less than exact in the case of these bulbs and ballasts.

George
 
Ditto Eugene. Far less than exact. "20K" bulbs, particularly Radiums, are a "species" of their own. This is a perfect example why Harker's equation shouldn't be used for all bulbs and isn't applicable to all situations for computing PAR.
 
Since the lux readings at the top of this thread show the Ushio bulb with a much greater lux reading than the Radium bulb and Sanjay's readings show that the Radium has a bit more PPFD on both the HQI and Blueline ballasts, I assume that the correlation between lux and par is less than exact in the case of these bulbs and ballasts.


I agree with what you guys are saying. Although you may want to ask Sanjay about those readings on that PFO HQI ballast and Ushio. If I remember correctly he did another test using a more up to date PFO HQI ballast, and a PAR rating of 160+ was what he come up with. Thus following along the lines that a higher lux can somewhat equate to more PAR, although not all the time.
 
By the way......I believe you can find that different PAR reading in the test he did when he had all the donor lamps/ballasts/reflectors, etc. I believe he presented it at the MACNA conference two years ago in Dallas.
 
George [/B][/QUOTE]I'm not familiar with the Harker article, but--based on one of the essays on Sanjay Joshi's website, and assuming that the lux readings here are accurate--there is not necessarily a direct correlation between lux and par[/QUOTE]


??? I do not why everyone keeps bringing up Sanjay into this thread. So what if HE did not find a direct correlation between Lux and PAR. Harker sure did. I fit the X values (Lux) and the Y values (PAR) to a linear curve using regression in Excel. I too get an R Squared values of 95.3%. Statistically speaking, you can't get much better than that. There is a correlation between Lux and PAR using the equation: y = mx + b within the range of x values given that b = 1.53, m = .0111, x = Lux values and y = the approximated value of PAR.

We just have to get Jason/Jeremy's Lux values to the same scale as Harkers. If their Lux values fall within the range of Harkers Lux values then one can interpolate a PAR value with a high degree of accuracy.

If outside of the range, then the danger of extrapolation rears it ugly head.

{QUOTE]How long a given bulb lasts on a given ballast is another issue, of course, but imo it is important not to make any blanket assertions about a particular bulb in the absence (or in the face) of verifiable testing.[/QUOTE]

What blanket assertions are being made here??? All Premium Aquatics are trying to do (correct me if I am wrong Jason/Jeremy), is trying to show the LUX values of some of the newer bulbs (CoralVue, PFO 13Kââ"šÂ¬Ã¢"žÂ¢s and XMââ"šÂ¬Ã¢"žÂ¢s) to the tried and true bulbs that have been around for awhile under identical conditions (i.e. same ballast, same reflector, same distance, ALL new). Many people have reported that the CoralVueââ"šÂ¬Ã¢"žÂ¢s appear brighter to their naked eye. Well, this data shows that this might be true for the blue bulbs (20K)! Forget the approximation for PAR values..just use the Lux vlaues.
No assertions being made hereââ"šÂ¬Ã‚¦you draw your own conclusions.
 
One thing that everyone needs to keep in mind is the varince in output from lamps of the same type can be large - particularly from manufacturers with low quality control standards.

Even in German made lamps, I have seen output differences between two lamps out of the same case of up to 17%. Larger variance is commonplace with lamps from the eastern countries that are making them for pennies on the dollar.

Also (if it's worth anything ;) ), I would say there is a correlation between Lux, and PAR, but without the use of a properly calibrated spectroradiometer, the results are always going to scew in favor if 475 nm + light because of the response curve of silicon diode measuring devices. I also believe that without knowing the spectral curve and doing some time intensive math, any equation would stray pretty far from accuracy. I would stick with the Lux measuements as J. and J. have been presenting and not try to compare to any past PAR measurements.

Interesting stuff guys. Thanks for the effort.

-Perry
 
10K XM's?

10K XM's?

Have there been any comparisons that include the 10K XM's (400W). I currently only have one (acquired recently) and will need to be buying 3 more 400W 10K's. Obviously a BIG out lay of cash regardless of the bulbs chosen. Please don't bother confusing me with facts! I am, in NO way dininishing all of the scientific discussion, I just want someone to tell me what's the best bulb to hang over my SPS's for good growth and a "white" look (not blue).
Thanks,
Tagamet, the village idiot.
 
Tagamet, I just changed out 2- 400W's for the new 400-10K CoralVues. I was in Premium Aquatics yesterday, & they appear brighter & more white than a 400K UShio. They had them side by side. Jeremy has not had time to lux them out yet but at $59 ea. you really can't go wrong. Of course, only time will tell on spectrum changes on the CoralVue, but I believe most will like their color rendition,Bob
 
Thanks

Thanks

Aged Salt said:
Tagamet, I just changed out 2- 400W's for the new 400-10K CoralVues. I was in Premium Aquatics yesterday, & they appear brighter & more white than a 400K UShio. They had them side by side. Jeremy has not had time to lux them out yet but at $59 ea. you really can't go wrong. Of course, only time will tell on spectrum changes on the CoralVue, but I believe most will like their color rendition,Bob

Well, the price is certainly great. Please keep us posted as they burn in over the next week or two.
Tagamet
 
Re: I don't think that more Lux necessarily = more Par

Re: I don't think that more Lux necessarily = more Par

I firmlyt believe your correct here. When looking at PAR value your realy looking at how much light is produced at specific wave lenghts. I also believe that you take this a step further and say that every bulb that is rated at a specific temperature does not produce the same ratio of light in all wave lenghts. This can even more be complicated by the true honesty of the manufacturers in there actual Color Temperature ratings. Than the final bit to add to the mess is that even bulbs of the same manufacturer only made out of different lots may possiby have different characteristics.

I personaly think Sanjay's articles on PAR values are some of the best I have seen. I would realy hope that he would do simular articles and studies camparing Comacts and T-5's.

Dennis


Eugene Reefer said:
I'm not familiar with the Harker article, but--based on one of the essays on Sanjay Joshi's website, and assuming that the lux readings here are accurate--there is not necessarily a direct correlation between lux and par. For example, in Sanjay's tests of various ballasts and bulbs the 400W Radium 20K bulb on either the Blueline electronic or PFO HQI ballast produced MORE par than the Ushio 400W 10K bulb, no matter what ballast was used for the latter. So in this case at least, more lux does not = more PAR.

Furthermore, in my experience at least very few sps turn brown under 400W Radium bulbs, and those that do likely do so for reasons other than lighting and eventually regain their original color (assuming that color was not the result of bleaching), or something very close to it.

How long a given bulb lasts on a given ballast is another issue, of course, but imo it is important not to make any blanket assertions about a particular bulb in the absence (or in the face) of verifiable testing.

George
 
I really wish that this testing that was done would not get compared to any other article floating around on the internet. Please take this info for what it is, a comparison of some of the older lamps on the market that we already know about, to some of the newer ones that havent had a chance to get tested yet.

Yes, we did just measure overall light output. But remember, the lamps that were tested were all "10k" and above, comparing to other "10k" lamps and above. I would think the majority of light these lamps put out would be in the 400nm to 700nm range. Since this is the range PAR is calculated in that would lead me to believe that the more lux these particular lamps put out, the higher PAR rating they would have. Of course that is speculation, and does not always hold true. But given the constants in this test, and the "kelvin" ratings these bulbs are listed at, I would feel pretty confident saying that linear regression would hold true in this case. Maybe we'll know for sure soon!
 
As I read through this post, the "200k" thing was confusing me.

Are there a range of settings like 200k, 20k, 2k, 200, etc on the meter???

If so the meter may be like a lot of DVM's that have what is called like a "three and a half digit" readout. You read from 0.000 to 1.999 as the range of the scale, THEN you multiply by 100 or 1000 etc (move decimal pt right x notches) to get the real value based upon the multiplier setting (range) you have selected.

I don't know why they end at 2, but maybe it has to do with the A/D conversion and some convenient binary number whatever....
 
Frick-n-Frags said:
As I read through this post, the "200k" thing was confusing me.

Are there a range of settings like 200k, 20k, 2k, 200, etc on the meter???

If so the meter may be like a lot of DVM's that have what is called like a "three and a half digit" readout. You read from 0.000 to 1.999 as the range of the scale, THEN you multiply by 100 or 1000 etc (move decimal pt right x notches) to get the real value based upon the multiplier setting (range) you have selected.

I don't know why they end at 2, but maybe it has to do with the A/D conversion and some convenient binary number whatever....

I believe that is precisely what the different settings are.

-Perry
 
Aged Salt said:
Tagamet, I just changed out 2- 400W's for the new 400-10K CoralVues. I was in Premium Aquatics yesterday, & they appear brighter & more white than a 400K UShio. They had them side by side. Jeremy has not had time to lux them out yet but at $59 ea. you really can't go wrong. Of course, only time will tell on spectrum changes on the CoralVue, but I believe most will like their color rendition,Bob

Aged Salt,

Any update on these lamps yet? I'm currently tied between the 10K XM, Ushio and Coralvue. Which one has the least amount of yellow?

Jeremy,

Have you gotten a chance to test/measure these lamps on the PFO HQI ballast yet?
 
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