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LED Wholesalers Rig?

Discussion in 'Lighting' started by Philosophos, Jul 6, 2009.

  1. SuperColey1

    SuperColey1 Guru Class Expert

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    .............CONTINUED

    This post is another comparison really and is not on equal terms. what I am using for the comparison is the cheap mirrored polished aluminium reflector (this is 1 month old and very clean. No dents etc. versus an expensive T5HO dedicated brushed 'white' aluminium reflector 2 years old but clean.

    On the left of the 1st pic is the mirrored reflector. It is a plain simple curve so I haven't taken a profile pic of it. On the right of the first picture is the brushed 'white' reflector. You can see how different in colour and texture the surface is. It is much stronger though.

    The profile you see is of the end of the T5HO reflector. I bought this as an all in one unit. It had a special electronic ballast that was housed within the hollow section. Then it was sealed with fixed end caps with the tube fitted. These were marketed as plug and play disposables in that they are not meant to have the tubes replaced.

    I bought 2 of these to 'downgrade' in March 2007 from 2.5WPG of CF to 1.8WPG of T5HO. Within a week of algae and huge plants I turned one off. lol. these were immeasurably better than the CFs.

    Unfortunately I wasn't very careful in storing them when I went over to LED hence why one reflector is now in 15 sections being used as heatsinking in the LED luminaire and this one is sitting waiting for a purpose. lol

    [​IMG]

    Onto the simple comparison. Below is a pic of 2 simple 3 LED (standard ones) push lights that I used. If I had used flourescent lighting you would not see any difference just 2 circles of white:
    [​IMG]

    Firstly we look at the normal reflection qualities from the reflectors. On the left you see that the mirrored one shows me taking the picture quite clearly. On the right the brushed white one shows absolutely nothing, not even a vague shape:
    [​IMG]

    What do they do with light?
    On the left the mirrored one shows 2 small lights and a little bit of light in other areas. Now look at the right. It isn't the shape that is doing that. Look at the central direct strike area. The light is huge in comparison. The shape will of course be better at redirecting the restrike but you can see by the surface of the direct area that the initial central hit is significantly better than the polished one!!!
    [​IMG]

    So I am looking at these 2 pictures and saying yes I can see that the better shape of the T5HO reflector is redirecting light much better away from the restrike area BUT that doesn't explain why the direct strike area show much improved performance on the T5 reflector's surface. The light that is hitting that initial are before redirection is showing a much higher reflection on the brushed one than the mirrored!!!

    I await some discussion now. lol This should set a few people going on something that I may well be totally wrong on.

    Regards
    Andy
     
  2. VaughnH

    VaughnH Lifetime Charter Member
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    Thank you all for a fascinating, but lengthy bunch of posts. While you were heading in your direction I was doing what I most enjoy, which is taking some data and using graphs, combined with basic theory to try to understand how and why things work as they do. I learned how to do this from my older co-workers at NASA back in the 1960's, and have always enjoyed it ever since. One of my most entertaining experiences there was when one of my mentors had a theory about something, which I don't recall, and he had me do some testing for data to support the theory. With great effort I finally gave him one data point, which I was only slightly confident about, and he immediately wrote a technical presentation about his theory. No amount of objecting I could do would stop him - he extrapolated the heck out of that single data point. Many months later, and many data points later, he found he was incorrect! But, he had a ball playing with that one data point.

    I feel like we are right at the edge of learning some important stuff about lighting an aquarium. So, I'm having a ball too!
     
  3. SuperColey1

    SuperColey1 Guru Class Expert

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    Am I making the wrong assumptions with the picture comparisons?

    AC
     
  4. VaughnH

    VaughnH Lifetime Charter Member
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    You are not wrong. One problem we humans have is that our brains automatically define "best" reflector as the one with a good accurate image in it - a mirror, for example. But, reflection of light has little to do with the qualities of a good mirror. A good mirror makes an accurate reflection of what light it does reflect, but that might be half of the incident light. By contrast, a pure white surface reflects all of the visible light, virtually 100% of it, but reflects no accurate image at all. Our eyes judge that to be a "poor" reflector.

    Years ago, in the small town where I lived, white painted houses were the rage, and white paint was as white as it could be made to be, which is very white. When the sun was shining on one of those newly painted houses the reflected light was so intense you would have a dark spot in your vision for many, many minutes afterwards. You just couldn't stare at such a house. Today, to solve that "problem" white paint isn't really white. It is always an off white.

    So, your salvaged T5 reflector probably reflects 90% or more of the incident light, while the polished metal reflector reflects a lot less. German Miro 4 material both reflects 90+% of the light and reflects an accurate image, so our eyes say "great" reflector, and it is.
     
  5. Philosophos

    Philosophos Lifetime Charter Member
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    Begin reply number one :D

    That's great. I've run across the other two sites as well at times, never given them a thorough look. I think the issue here is not whether the knowledge is out there, but whether or not its consolidated in to an easily referenced source. There are just misserable books and inaccurate articles that get better attention with new hobbyists than all 3 of those sites combined. I'd like to see that change, and maybe help with it if I can.

    I'd agree with this most of the time. There are occasional exceptions. ADA AS costs the same or less than DIY versions that I've tried to work out. Putting together your own filters on tanks
     
  6. Philosophos

    Philosophos Lifetime Charter Member
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    And without much delay, reply #2

    Wouldn't a dull surface decrease the actual concentration of light, simply because of the diffusion? The restrike of the photons changing angles would cause more issues than if they only bounce once or twice, wouldn't it?

    -Philosophos
     
  7. SuperColey1

    SuperColey1 Guru Class Expert

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    This is a 2 way house really. It lets the user use a near copy of the original so they are still reassured they are using something safe. It may pull them from a product they know works over the the realms of dabbling. It also lets others see what is there and investigate why some products are so succesful and why others aren't worth their salts. excuse the pun

    On the lights where I mean the print is different I meant one has AQUARIUM printed on the tube and the other doesn't. lol

    Do Tom and the team here not fit the bill ;) He frequents many forums too so the word does get spread around. Those who choose not to listen will listen to no man unless it is the 2 bit reporter on CNN. lol

    I'm going to see if anyone I know has a laser pen to test this little theory. I'm sure the lowlife idiots around this social housing area I live will have one somewhere saved up to try and blind aeroplane pilots or shine in footballers eyes!!!

    I guess then you could work out from the charts Vaughan is doing that if the PAR directly below is X Par at N distance that even on the angle this would hold up to Y Par at M distance.

    What I found was that there were many willing to listen until the long standing members decide they are losing the limelight and suddenly burst in on every thread. It is often the same people on every thread as if they are clicking on my name and then seeing what new posts I've made. They try to make you out to be bad for confusing the OP with a conflicting opinion. Better to have 1 right opinion from an algae free tank owner amongst the many incorrect answers from the Excel spot dosing team :D

    I get asked for published papers etc. I can't really be bothered to fight my corner in that respect. I would rather help others on other posts and maybe enjoy other things than to be trawling the net for evidence that agrees with me. Waste of time really. If I did that and supplied them with matching evidence they would do the same and search for the conflicting evidence. Would get nowhere so I provide my side, argue it a little and then leave the OP to decide. On some forums someone in the know will chime in and back me up. On others they don't and I can accept I may be wrong but I will question why first.

    It annoyed me in the first spell I went on there and I left for a long time. Now I go on there and argue the toss until it is just getting to argument status.

    I hear people talking about MH and LEDs creating shimmer that you can't get with flouros???? Are they sure? When I raised my luminaire up still fitted with the flouros (getting ready to put the LEDs in I got shimmer. Is it not just a case of we put flouros closer to the water using less wattage whereas the other 2 are raised?

    I have some Rotal Rotundifolia, Bolbitis, Lileopsis and Crypt Wendtii growing in compost in underbed storage boxes (L 3ft x W 2ft x D 1ft) in my garden. will the daylight do :) I can get a pot of HC and start one in the artificial single tube setup, 1 under the pink, 1 under the green and 1 under the daylight. All growing on the same compost. These ones here are grown under the 18W daylight and take about 4 weeks to quadruple in size. A small area maybe 2cm is put in the middle, just laid on top ofthe rockwool, not planted or anything. I position it, it roots itself and then grows:
    [​IMG]

    On the subject of the dull versus shiny. Maybe a crude test could be done using both side of some tin foil? Wouldn't be ideal but it should show which is higher.

    AC
     
  8. Philosophos

    Philosophos Lifetime Charter Member
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    Maybe some day, not yet. Nobody I've talked to in person around here knows about this site or EI. On the other hand, most have heard of Axelrod between his books, one of the fish named after him, or TFH magazine.[/quote]

    Great idea, go mug a chav for science ;)

    Taking science personally is the surest way to mess up a good peer review process. Not that most threads are scientific, but we should at least attempt to be objective. This being ruined, I'd call it an invitation to drama. Let me know if you run in to this sort of thing again; I've got a couple ideas.

    I only head out for papers when I know my premise is based on established principles. Anything else is inductivism; might as well be putting saddles on dinosaurs in museums.

    You got a shimmer with fluoros? I'm ordering in a slightly overwatted system, should be here at some point early next week. The DIY portion should be done by about this time next week. It's 2x54w T5HO, which is hopefully enough to be raising the rig up a little. Either way, I'll try suspending it up high temporarily to look for the effect.

    Daylight gets tricky if it's purely outdoors. Changes in temperature and humidity, plus the extra dose of UV creates some fairly unsteady variables. It'd be better to test under lamps if possible.

    I don't think there's any way a rough/dull surface will reflect more light in total, when measured thoroughly with a PAR meter. The physics seems all wrong. I do think that a duller surface will create more even spread, and then perhaps faster growth.

    -Philosophos
     
  9. SuperColey1

    SuperColey1 Guru Class Expert

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    I may make sure I was right to confirm this but I think it was turbulent water surface which gave the shimmer.

    Shimmer doesn't seem to be something that you get in clam water if you know what I mean and I would guess it takes multiples tubes too.

    You should get it I would think but I don't know why anyone would want to overpower to do it. With LED I aimed for less light and got more and had to raise. the multiple sources of light created the shimmer. I see no reason why multiple points of light even with it being in the form of 2,3,4 tubes wouldn't also create this effect.

    AC
     
  10. VaughnH

    VaughnH Lifetime Charter Member
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    The intuitive answer is, of course, that a shiny surface has to reflect more light. But, intuition isn't always right. My own experimenting with different reflector surfaces showed that plain white paint reflects about the same amount of light, measured with a PAR meter, as a shiny aluminum foil, and more than aluminized mylar mirror-like material. And, that was with a random spray can of white paint I just happened to have on hand.

    After that experiment I did a lot more reading and learned that there are white pigments that reflect very close to 100% of the incident light - diffuse reflection, of course, but for an aquarium light, diffuse reflection can be better than specular reflection.
     
  11. VaughnH

    VaughnH Lifetime Charter Member
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    The shimmer effect you get with LED lighting isn't necessarily a good thing. I maintain a very rippled surface on my tank, so the shimmer from the LEDs gets to be annoying as often as it is charming. I have had shimmer with the PC bulbs I used to use, but it was very subtle compared to what the LEDs give.

    The reason for the shimmer is that LEDs are the closest thing to point sources of light that we have. And, a point (or line) source of light will project a shadowgraph of any variations in index of refraction, or anything else that changes the path of the light even minutely. Each individual LED is projecting a shadowgraph of the water surface its light passes through onto the substrate and plants.

    Years ago when I was working with aerodynamic flow visualization at NASA, we often set up shadowgraph equipment, using a slit to get a line source of light, to be able to see the density variations of air flowing supersonically over a model. I found this to be fascinating, and extremely difficult to make work well. Now, my LEDs are doing it with 24 conflicting shadowgraphs all projected at once for my "enjoyment". This may be the Achilles heel of LEDs.
     
  12. SuperColey1

    SuperColey1 Guru Class Expert

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    Indeed very true. When I first setup the test of the LEDs with 3 it was a pleasant subtle shimmer. When I went up to 15 it was like a disco strobe lighting and you couldn't look for very long just as you experienced. I raised it up anyway as the light was too much and this reduced the shimmer.

    One thing that confuses me is that the reason I see that flouro can do it when raised a bit higher is from the dual/triple sources of light moving through the surface. When my LEDs do it it is much more because of the 15 sources.

    Why do single bulb MH do it?

    AC
     
  13. VaughnH

    VaughnH Lifetime Charter Member
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    MH bulbs are the closest we have to a point light source, after LEDs. A single point light source does produce a single shadowgraph of the water surface ripple, but because the ripple moves, the shadows move. That is how I uderstand it anyway. I still have trouble understanding why tube light sources can do it.
     
  14. Philosophos

    Philosophos Lifetime Charter Member
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    Ok, so for the reflector color, the fact that the light is diffused is negligible at standard aquarium heights? Or is there no difference at all? It would seem that sending photons off in strange directions would decrease light level in a given area, over enough distance.

    Thinking on the topic of rippling, wouldn't any well distributed light cause this? Strong, direct penetration through surface ripple from high light at close range shouldn't alter the majority of the path of the light. By comparison, a number of spread out weaker lights, or better diffused single points would cause a weaker source of light to be more easily deflected by a slight ripple.

    The forum got busy while I was gone. Is someone doing PR?

    -Philosophos
     
  15. VaughnH

    VaughnH Lifetime Charter Member
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    The shadows of the ripples are apparent only if they are focused on the substrate and plants. A diffuse light source can't cast a sharply focused shadow, if it casts a shadow at all. Light coming through the ripple from various directions will cast many shadows which will blur them all together, making them invisible. At least it should work that way. But optics can be strange at times.

    Multiple LEDs are not so numerous as to cast enough shadows to blur them. Even that is probably more true with the moving shadows, which make them much more visible. With plants near the substrate, you do see multiple, non-moving shadows, as each LED casts a different shadow.
     
  16. agv180

    agv180 Junior Poster

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    Hi
    I am from Colombia, I would like to know wich substrate you use for the unsubmerged crop?, Also, do you live your lights on all day?, Do you use fertilizer, how much?. Thank you
     
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