Please set me straight (light studies)....

[jlehigh]

I hardly know where to begin...

I went back and looked at Sanjays articles on the 400W DE's. The conclusion was that the bulbs were comparable to SE's and the reflectors were as well.

I tend to question the conclusion on the reflectors based on the data given. The reason being the IceCap reflector with a 400W DE 10K bulb far outperformed a SE 400W 10K bulb in a lumenarc3 (by about 1700 ppfd at 6" 1500 ppfd at 9" and 1200 at 12")... This also suprised me because the icecap reflector is a long and skinny rectangle. Regardless it's PAR readings were 40% more intense.. I wouldn't call that comparable...

Given the Lumenarc3 is by far the best SE reflector it makes me wonder if a DE bulb would in fact outperform the SE's.... My head is already spinning at the moment.

Only one of the two 400DE setups tested outperformed the SE but now I dig in further. The SE used in the comparrison was the absolute brightest combination in the SE studies. It used the Ushio 10K bulb OVERDRIVEN by an HQI ballast on the Absolute BEST SE reflector (Lumenarc3).. The 400DE samples were using pendant reflectors with only the few bulbs that were available at that point in time (Avalon and Icecap bulbs).

I would think that the 400DE's strongest combination of ballast/bulb and reflector far outperform the strongest combination of 400W SE's and it would seem they do given the difference in ppfd in Sanjay's 400DE reflector study.

Even though these ppfd differences are peak differences the light distributions aren't all that different either.

What am I missing here? Why is it concluded that 400W DE's are comparable to 400W SE's? The only numbers I saw close to each other was the total incident light.

"A reflector's total incident light upon a surface of a given area is representative of the performance of a reflector. It is computed by adding up all the measurements taken at the discrete points within the region. It demonstrates how much light the reflector is able to focus downward when compared to other reflectors with similar operating conditions"

http://www.advancedaquarist.com/issues/dec2004/feature.htm

 

[jlehigh]

Okay I have to add more:

So instead of using the Luminarc as the comparison, lets look at the PFO SE reflector using a 400W SE bulb. I would be interested in this because the two reflectors are much more alike.

The PPFD reading are far below that of the 400DE in the IceCap Pendant. At 6" the PFO pendant using the 400W Ushio 10K SE was 2147. total incident light was 45388 in 3X3 area

At 6" the IceCap pendant using the 400W 10K DE bulb was over 6000. Total incident light of 67182 in 3X3 area..

See where I'm going with this?

 

[smonroe]

that you have too much time on your hands?

j/k I think your points are valid and hopefully we can get some clear insight as to differences mentioned any takers?

Stan

 

[Scooterman]

This was a 4 part study, so I didn't refresh myself on all 4 parts. I think it was given for some time that you do get higher peaks than the SE. Some of the major issues is heat, lamps having to be covered from exposure, handling the lamp, UV filter required. If your hanging a pendant over an open tank, with no hood, you can take advantage of the extra kick you get.

 

[jlehigh]

Thanks for the input Scooty:

Right, the studies spanned 150W 250W SE&DE, 400's and all relevant/irelevant reflectors

Just to share my background a little bit. I saw the completed studies at a glance and accepted that 400DE's were'nt much better but I liked the 20K coloration and intensity so I picked up three 400W DE kits. I did have a lil time on my hands today and went back to see what PAR I was getting, but then the numbers didn't add up for me..

The kits I have are pendants hanging over my tank for a rail system I built. All came with glass shields to protect from UV. They do get hot though. I have a fan that blows across the tank.. I've been runnign them for about 4 months now and really like them.

 

[Scooterman]

With lighting like that, if you can't grow an sps coral, it is something else wrong The funny thing when it comes to lighting, you can get good arguments back and forth over so many different combinations ideas, it is crazy. Within reason you will get good results with the majority of the modern lighting, none perfect but results are positive for a good bit of them. Two kinds of people I see, one want the most bang for their buck, & the ones that wan every bit they can get, so you have to fit the needs of the many, price & coloration is most discussed.

 

[mojoreef]

Personally O dont like the DE units as the spread is alot skinnier and more of a focused beam. that and once over your tank the E glass always needs cleaning.

jlehigh I think this question is best answered by Sanjay. I will shoot him a email and ask him to pop in.


MIke

 

[jlehigh]

Thanks Mike. Yea every unit has it's good and not so good. I am just interested in seeing a pendant to pendant comparison versus a pendant to luminarc.

I also have a thread on Garden Supplies vendor forum on reefcentral to talk about possible luminarc DE retros or a new product.

 

[sanjay]

Personally O dont like the DE units as the spread is alot skinnier and more of a focused beam. that and once over your tank the E glass always needs cleaning.

jlehigh I think this question is best answered by Sanjay. I will shoot him a email and ask him to pop in.


MIke

Ah.. yet another case of justifying your purchase

As someone already pointed out in this thread, you can grow corals with a lot of the available combinations.

You first need to establish what is it you want, and at what cost. ? Everyone has a different value system they apply to choose the lighting.

As for 400W DE vs.. sure there are combinations of 400W DE that will clearly outperform the 400W SE.

The issue with the DE hype is as follows:

1) Do the DE lamps have more PAR than the SE lamps ? If we take the best DE combo of lamp and ballast and compare to the best SE combo out there for same color temp lamp, then as you can see from the data the difference is quite small ( I usually discount anything within a 10% range).

OK.. so next... Do the DE in thier reflectors do better than the SE ? Again, I compared the best in class to the best in class. And at that level once again the difference is not very significant. As you have noted that the ICECAP does hit higher peaks... but once again is that what you want ? I would prefer a lower peak and a larger spread which I get with a LA3 reflector.

The lamp that I used in the scaled model of the LA3 was the XM10000K, which had the most PAR of the 10K SE lamps. If you use a Ushio 10K on a mag ballast surely the DE will outperform it.

sanjay.

 

[jlehigh]

Thanks for dropping in Sanjay!

No need to justify my purchase. If I needed to do that I would spend the next 3 years in private and personal cranial chaos computing the thousands spent on my 300gal system and all the trips to Bali I could have taken in exchange

I understand the importance of taking a step back and looking at the big picture. I saw reason to question how comparable the two products were based on the hardware being used in the comparrison.

I agree both would perform well in tanks keeping SPS ect, but I also see allot more spider-type and pendant reflectors than Luminarc3's for various reasons (space and money). I would almost see the Luminarc3 stats being an outlier statistically because it so outperforms the rest. I would venture to say the luminarc3 is not for the average hobbyist rather the advanced because of the additional spacial and financial commitments that come with the package.

I have been talking with Garden Supply about developing a retro or new reflector for DE bulbs for two reasons: 1. The light distribution is better suited for the shape of my tank. 2. Darn curious how the DE's would perform in them..

Thanks again Sanjay, I reference your spectral output analysis articles all the time

 

[sanjay]

One of the reasons for comparing the 400W DE with SE using LA3 was primarily to show that similar results could be achieved by the SE lamps. As for cost.. those 400W DE systems + bulbs will run you a lot more than the Lumenarc + bulb.

Space is ofcourse a constraint that must be considered.

I am not really interested in pushing any technology or approach to reefkeeping, but more interested in being able to make decisions based on data than heresay, and empower people to make thier own decisions based on real data. Plus I am interested in running a reef at the lowest possible cost and still be successful

sanjay.

 

[Scooterman]

Thanks for the great information SJ!

 

[jlehigh]

Just in case it will help folks looking at these options here is a high level breakdown:

Optimal 400W SE Set-up
L3 reflector + adjustable bracket - 125.00
400W SE Bulbs - 60 (Coralvu) to 120.00 (aqualine)
400W HQI Ballast - 160 (PFO)

tot - 345.00(low) 405(High)

400W DE Kits
These kits include HQI ballast, Bulb of choice and Pendant
Coralvu kit - 329.99
PFO Kit - 349.99 (my reccomendation after trying both)

(Bulb replacement costs vary from 100.00 to 120.00

All prices were pulled from an excellent sponsor of ours Custom Aquatic who I find to be very competitive. L3 pricing was a quote given over the phone.

 

[jlehigh]

I'll add the dimensions too:

L3- 19.5” x 19.5” x 8.5” tall
PFO Pendant - 14" x 11 x 6" tall

 

[mojoreef]

Sanjay thanks for dropping in and helping out with the thread.


Jlehigh Good thread and good info...thanks


Mike

 

[jlehigh]

Definately glad to have you both here on Reeffrontiers and mojo in my backyard!

I thought I would paste the reply I recieved from Garden Supply on DE Retros for Luminarc reflectors:

First off, we don't recommend DE bulbs, and our hoods are not designed for them, that said, the hoods are symmetrical, and so are the bulbs, so it should be possible. Our brackets have two slots for sliding the socket in and out of the hood. Our thinking would be to cut and attach an adjustable socket and bracket to the other side of the hood, and slide to fit the bulb... however our sockets are mogul bases. You could get a second bracket, and juryrig a new DE socket onto something that would fit the sliders on the bracket, allowing you to adjust the bulb.

I was curious as to why they do not reccomend DE bulbs (I venture to guess heat and shielding), but I will let you know if they respond to my request for a brief explanation.

I can keep folks posted on any developments, but if I am the only one curious let me know that too and I'll shut-up

 

[mojoreef]

Always looking for more knowledge J


Mike

 

[sanjay]

Thanks Jlehigh for the $ numbers. I had not priced these things in a while. Good to see that the DE setups are being priced in close to the SE. Now they just need to bring the lamp costs down... will happen with increase in volume and competition.

Will be interesting to see what they say about retrofitting DE lamps in thier reflector.

sanjay.

 

[bc_slc]

What great thread. Jlehigh, great to see someone getting down to the meat of tough questions. i know that as somewhat of a novice, that lighting was one of the things that baffled me. Had it not been for moonpod on RC, I would have wandered entirely in the wrong direction.

And sanjay, thank you so much for stopping by. No better person to direct questions in regards to lighting comparison in my opinion. Much appreciated.

Mat

 

[jlehigh]

Thank you for the possitive feedback. Being an analyst aka anal-ist sometimes leads down unproductive paths

Here is the repsonse from PGS (more or less what I expected)

Other than the heat and expense, there is also the added UV, which then requires a UV protectant glass shield of some sort. Which makes me wonder if the added light from a DE bulb worth all the hassle, when you could just as easily increase the wattage on a mogul and get more light.

I also don't recommend them because they don't fit in our hoods. *wink*
Or atleast, not currently, expect L4 pics ASAP.

If I had lighting "issues" I would probably try to retro an L3, but at this point I would be doing it just out of curiosity. We'll see... I am VERY interested in those L4 pics.