No love for MH?

[hart24601]

Its actually an opinion and a claim - based on an observation. Here is another observation - the vast majority of people who have read the poll and taken it are not - and are not planning to use MH lighting. Why do you think this is? Not a rhetorical question - I'm just wondering if you can step outside your opinion - and try to think about why others don't agree?

I know this is not a question at me, however I do have a great example of someone who went MH recently then away. In our local forum he posted about lighting options and we talked in some detail but he was pretty convinced to switch off his lighting at the time to MH 100% because of a few very convincing people here on reef2reef despite my best intentions trying to warn him it may not be quite so cut and dry.

Well about 2 months later they were all for sale - heated his office up far too much without any noticeable improvements. Granted 2 months may not have been long enough to see any presumed improvement, but was long enough to experience disadvantages. Don't know if he ever sold his nearly new equipment, I'm sure was am expensive lesson.

 

[A. grandis]

Its actually an opinion and a claim - based on an observation. Here is another observation - the vast majority of people who have read the poll and taken it are not - and are not planning to use MH lighting. Why do you think this is? Not a rhetorical question - I'm just wondering if you can step outside your opinion - and try to think about why others don't agree?

They don't know metal halides and chose not to without knowing but they say that after others. They know not what to expect in terms of results. Some hear about the results but don't want to change for some reason.
Lack of knowledge and experience in the hobby. Novice.
Or they adopt their excuses like chiller failed, too hot, too much electricity, etc..
Can be anything.

 

[A. grandis]

Fair enough. That’s just my assessment of it. I don’t expect a big upswing in metal halide users to the point it begins being marketed by the major retailers again as a must have product or that the old timers will suddenly reactivate their old RC accounts and start posting again. I think there will just continue to be a handful of people who continue using them because they are happier with how they perform, and eventually most new hobbyists will be unaware of what a metal halide lamp even is

I actually expect more and more people to use halides. We see people experimenting and the numbers growing every day here. Some years ago there wasn't any possibility for any thread taking about halides. Now we see it as the subject of the hour. Proof that people actually see differences and improvements when they try. Too bad many of them don't participate here and tell their testimony. Some did though, so...
Time will tell.

 

[TheGreatWave]

How come you use a hood with your Halide bulb?

 

[Bpb]

How come you use a hood with your Halide bulb?

I do because I hate light spilling into the room. A canopy over the tank is non negotiable. I have used the same canopy when I used leds

 

[TheGreatWave]

If light is reflected, does it reflect it's source in high fidelity, or is the new source an amalgamation? Is the light off a reflector still MH light?

The simple answer for us novices here as to why MH worked at all, IMO:

It's a big light bulb. What other fixture does 250w/400w/600w/or 1000w of blue light from a single bulb? What does this mean? Well if you had a 30" or deeper tank and want to grow SPS on the floor you traditionally needed the punch of really big discreet bulbs because florescent are a flood light with wide shallow soft distribution. Theoretically off the cuff calculations a LED can put the same light in the tank using less then half the power of a bare MH bulb, just because it faces the right direction compared to a bare MH bulb.

Now I know a good portion of the MH light is captured and redirected into the tank, but at what ratio? Is it usable PAR or just visually less shadows? Is it "MH light" or a different spectrum that is reflector dependent? Could the same or better results be achieved with multiple point sources rather then reflected flood light?
Does anyone have the ability to cover up the MH bulb and measure the spectrum of the reflected light alone?

Since MH bulbs throw more then half the light in the opposite direction, reflectors are used, it's reasonable and practical, I get it. The reflector is responsible for reducing shadowing. Otherwise MH shadows just like LED, maybe a little less due to the brute force lighting bouncing off everything in the room.

I offered up a scenario before that was somewhat acknowledged by Oreo. You could in theory make a big LED bulb and use it with a reflector if you wanted.
It would however be more efficient to spread the diodes out and point them down.

It is useful to think of light as shape and power.

A MH fixture is a hybrid fixture. It has a central hot spot that punches down deep directly, it also has an surrounding envelope of soft flood light caused by the reflector, a passive radiator. The reflected light travels farther and is weaker, but it's better then wasting it completely. It was a happy accident caused by using this light in the near-field. It has absolutely zero to do with coral "pigment formation".

It's not that I am ignoring spectrum, it's just that the same crowd touts a 6500K bulb as the best grower while also debating specific magic blue bulbs of particular wattages with certain kinds of UV.
Spectrum is it's own thing independent from shape, power and type of emitter.

 

[Bpb]

If light is reflected, does it reflect it's source in high fidelity, or is the new source an amalgamation? Is the light off a reflector still MH light?

The simple answer for us novices here as to why MH worked at all, IMO:

It's a big light bulb. What other fixture does 250w/400w/600w/or 1000w of blue light from a single bulb? What does this mean? Well if you had a 30" or deeper tank and want to grow SPS on the floor you traditionally needed the punch of really big discreet bulbs because florescent are a flood light with wide shallow soft distribution. Theoretically off the cuff calculations a LED can put the same light in the tank using less then half the power of a bare MH bulb, just because it faces the right direction compared to a bare MH bulb.

Now I know a good portion of the MH light is captured and redirected into the tank, but at what ratio? Is it usable PAR or just visually less shadows? Is it "MH light" or a different spectrum that is reflector dependent? Could the same or better results be achieved with multiple point sources rather then reflected flood light?
Does anyone have the ability to cover up the MH bulb and measure the spectrum of the reflected light alone?

Since MH bulbs throw more then half the light in the opposite direction, reflectors are used, it's reasonable and practical, I get it. The reflector is responsible for reducing shadowing. Otherwise MH shadows just like LED, maybe a little less due to the brute force lighting bouncing off everything in the room.

I offered up a scenario before that was somewhat acknowledged by Oreo. You could in theory make a big LED bulb and use it with a reflector if you wanted.
It would however be more efficient to spread the diodes out and point them down.

It is useful to think of light as shape and power.

A MH fixture is a hybrid fixture. It has a central hot spot that punches down deep directly, it also has an surrounding envelope of soft flood light caused by the reflector, a passive radiator. The reflected light travels farther and is weaker, but it's better then wasting it completely. It was a happy accident caused by using this light in the near-field. It has absolutely zero to do with coral "pigment formation".

It's not that I am ignoring spectrum, it's just that the same crowd touts a 6500K bulb as the best grower while also debating specific magic blue bulbs of particular wattages with certain kinds of UV.
Spectrum is it's own thing independent from shape, power and type of emitter.

That’s a good question. Does the 95% or whatever reflective surface reflect the UV and IR waves also or so they penetrate/become absorbed by the reflector? If we look at photons in a basic sense, not all photons can be reflected. They behave differently at different wavelengths. Extremely short wavelengths are unable to be reflected and they will either penetrate or be absorbed. Where is the cutoff? Is the good juice from a MH bulb only emitted from the primary beam, and only various wavelengths of visible light contained in the secondary scattered/reflected beam? Good topic there. Where is the cutoff on reflection vs attenuation or penetration?

 

[jda]

...again, all comes down to breath and depth of experience. The tech does not matter, as Oreo illustrates in the converse... since it is economics and physics that matter and nobody has over come them.. who cares if a LED can be created to eliminate shadows when nobody has done it. Who cares if a MH is a point source without a reflector since nobody uses them without one. As more and more of you get some breath and depth of experience, please at least post back as to how your opinions have changed. If you cannot at least see that there are things that you are missing using LED, then you don't have enough of either yet. Most people just disappear, and the cycle continues, but some will actually come back and amend their noobie conclusions and arguments.

Some of you are so new that you don't even know that a 6500k bulb and the sun has a massive amount of blue and UV in it.... one of the other reasons why it does such a good job. Just because it does not look blue to a poor tool such as the human eye, does not mean that it is devoid of blue, or UV. ...takes some time to learn all of this, I guess.

 

[Bpb]

Gotta love the old “don’t use 6500k bulbs because they can’t penetrate past 24” deep so they’re only good for very shallow tanks”. Funny

 

[oreo54]

R

 

[TheGreatWave]

...again, all comes down to breath and depth of experience. The tech does not matter, as Oreo illustrates in the converse... since it is economics and physics that matter and nobody has over come them.. who cares if a LED can be created to eliminate shadows when nobody has done it. Who cares if a MH is a point source without a reflector since nobody uses them without one. As more and more of you get some breath and depth of experience, please at least post back as to how your opinions have changed. If you cannot at least see that there are things that you are missing using LED, then you don't have enough of either yet. Most people just disappear, and the cycle continues, but some will actually come back and amend their noobie conclusions and arguments.

Some of you are so new that you don't even know that a 6500k bulb and the sun has a massive amount of blue and UV in it.... one of the other reasons why it does such a good job. Just because it does not look blue to a poor tool such as the human eye, does not mean that it is devoid of blue, or UV. ...takes some time to learn all of this, I guess.

I was a community teachers assistant at M.I.T.x for 2 years and have a certificate of mastery in electronics in circuits, lets not be so quick to assume what people know or are capable of learning. What I learned most about electronics, is that I really don't know anything about electronics. ;) Time spent on something and experience is not a linear equation.

Where did I state that I was unaware blue was a component of white light? (They teach this in grade 5?) When did I say or even remotely imply that a 6500K bulb has no UV. (Ignoring for a moment that most SE bulbs have a built in UV shield)

I care about the reflector because it blows a hole in your argument for MH superiority, at least in regards to shadowing.
I see BRS videos with 10 or 12 XR-15 LED eliminating shadows.

Did you read that paper Oreo posted about light sources and porosity :

"No significant differences were registered in the porosity of the skeletons of the monoclonal fragments of A. formosa (45.32±7.59%, 53.63±5.34% and 52.45±2.41% for T5, LED and LEP, respectively; DF = 2, F = 1.980, p = 0.2186) or S. pistillata (27.52±1.58%, 25.61±0.68% and 27.06±3.82%, for T5, LED and LEP respectively; DF = 2, F = 0.508, p = 0.6255) grown under the different light treatments. "

Did you read the one about UV:

"Increased UV radiation alone significantly decreased the F(v)/F(m) of all coral species, even at 27 degrees C. "

It gets worse with your hot light :

"There was a combined effect of temperature and UV radiation, which reduced F(v)/F(m) in all corals by 25% to 40%. "

The differences in shape of corals noticed in the first paper can easily be attributed to the shape of the light.

 

[jda]

You got the wrong guy with the porosity or thin skeleton thing. That is not me who is on that one. I am not arguing that one at all.

The glass shield removes the harmful UVB and any UVC (if any, which it does not appear that there is). The UVA still gets through... you can see this in any chart, but you probably knew this too and also that it gets to corals in the ocean, helps with coloration, develops colorful pigments that act as sunscreen, true coloration for some proteins, emittance at lower energy in the visible spectrum making more color and most proteins can use it for energy. Also, that some of the higher end panels have already added it and others are expected to join in. I would not be so quick to dismiss the importance of UV in the 350-400nm range. This is likely one of the real reasons why most LED panels are still behind T5 and MH in coloration. Nor do I care about an experiment where corals got UV alone... what good is this? I know that these corals that are nearly all collected on one breath get UV in the ocean just under the water... and assuming nature gets things right, until proven otherwise with scientific method, like any good scientist (and not that we have to prove that nature is right.. pseudoscience, which is too much reef science), then they have adapted/evolved to use UV as a resource available to them.

I think that it is important for people to know how to take your posts. Do you hobby, or are you an interested passer-by without any real experience with a reef tank like Oreo. Both can be helpful, but both also come from a different place and posts need to be weighed accordingly, although the passer-by seems to nearly always think that they don't need to experience what they are typing.

 

[TheGreatWave]

That’s a good question. Does the 95% or whatever reflective surface reflect the UV and IR waves also or so they penetrate/become absorbed by the reflector? If we look at photons in a basic sense, not all photons can be reflected. They behave differently at different wavelengths. Extremely short wavelengths are unable to be reflected and they will either penetrate or be absorbed. Where is the cutoff? Is the good juice from a MH bulb only emitted from the primary beam, and only various wavelengths of visible light contained in the secondary scattered/reflected beam? Good topic there. Where is the cutoff on reflection vs attenuation or penetration?

All the more reason to keep those nitrates low. Although I think synthetic seawater is more transparent then natural seawater to UV, so that works to offset our poor husbandry lol.

What effect do you think adding a polarizing filter to your light would have on coral growth?

 

[DogsRule]

I was a community teachers assistant at M.I.T.x for 2 years and have a certificate of mastery in electronics in circuits, lets not be so quick to assume what people know or are capable of learning. What I learned most about electronics, is that I really don't know anything about electronics. ;) Time spent on something and experience is not a linear equation.

Where did I state that I was unaware blue was a component of white light? (They teach this in grade 5?) When did I say or even remotely imply that a 6500K bulb has no UV. (Ignoring for a moment that most SE bulbs have a built in UV shield)

I care about the reflector because it blows a hole in your argument for MH superiority, at least in regards to shadowing.
I see BRS videos with 10 or 12 XR-15 LED eliminating shadows.

Did you read that paper Oreo posted about light sources and porosity :

"No significant differences were registered in the porosity of the skeletons of the monoclonal fragments of A. formosa (45.32±7.59%, 53.63±5.34% and 52.45±2.41% for T5, LED and LEP, respectively; DF = 2, F = 1.980, p = 0.2186) or S. pistillata (27.52±1.58%, 25.61±0.68% and 27.06±3.82%, for T5, LED and LEP respectively; DF = 2, F = 0.508, p = 0.6255) grown under the different light treatments. "

Did you read the one about UV:

"Increased UV radiation alone significantly decreased the F(v)/F(m) of all coral species, even at 27 degrees C. "

It gets worse with your hot light :

"There was a combined effect of temperature and UV radiation, which reduced F(v)/F(m) in all corals by 25% to 40%. "

The differences in shape of corals noticed in the first paper can easily be attributed to the shape of the light.

I could quote your line directed at me earlier - "Oh please spare us the hyper...." but I won't, because you deleted it, so will leave it at that.

When I first used MHs on reef tanks (even mediocre softie ones to quote you again), there were no reflectors, but there was no issue with shadowing either. It didn't matter if this was a tank lit with a single bulb (can't get much more point source than that) or more than one. I fixed a square of flashing to the inside of the canopy to stop the canopy possibly catching fire & didn't care about any reflective qualities the flashing had. When reflectors for MH bulbs started to become popular, there was still debate on if they worked, but could they actually damage the bulb due to re-strike (or whatever it was called at the time). I can't ever remember the issue of dealing with shadowing coming up though.
The one downside to MH being so point source is having to use lights in between aquarium cross braces. I could light my current 6ft tank with 2 MH & have great results, but the cross braces dictate I need 3 bulbs ( I believe you called that insane). I've lit a 4ft tank (no cross brace) with a single 250 MH- now that is insane.

 

[Bpb]

All the more reason to keep those nitrates low. Although I think synthetic seawater is more transparent then natural seawater to UV, so that works to offset our poor husbandry lol.

What effect do you think adding a polarizing filter to your light would have on coral growth?

I would thing polarized lenses over a tank would be bad. The light scatter going into the tank is a good thing

 

[TheGreatWave]

I could quote your line directed at me earlier - "Oh please spare us the hyper...." but I won't, because you deleted it, so will leave it at that.

When I first used MHs on reef tanks (even mediocre softie ones to quote you again), there were no reflectors, but there was no issue with shadowing either. It didn't matter if this was a tank lit with a single bulb (can't get much more point source than that) or more than one. I fixed a square of flashing to the inside of the canopy to stop the canopy possibly catching fire & didn't care about any reflective qualities the flashing had. When reflectors for MH bulbs started to become popular, there was still debate on if they worked, but could they actually damage the bulb due to re-strike (or whatever it was called at the time). I can't ever remember the issue of dealing with shadowing coming up though.
The one downside to MH being so point source is having to use lights in between aquarium cross braces. I could light my current 6ft tank with 2 MH & have great results, but the cross braces dictate I need 3 bulbs ( I believe you called that insane). I've lit a 4ft tank (no cross brace) with a single 250 MH- now that is insane.

I had a post moderated. I stand by my comment of your 750 watt tank as being insane lol. In context of course, it's now lost it's pizazz.

 

[TheGreatWave]

I would thing polarized lenses over a tank would be bad. The light scatter going into the tank is a good thing

It seems that reef fish us it for navigation, I often wonder what, if any effect it has on the growth pattern of wild coral.

 

[chefjpaul]

So because you run MH indicates that you are a "more serious " hobbyists than those that dont?

 

[shred5]

You got the wrong guy with the porosity or thin skeleton thing. That is not me who is on that one. I am not arguing that one at all.

The glass shield removes the harmful UVB and any UVC (if any, which it does not appear that there is). The UVA still gets through... you can see this in any chart, but you probably knew this too and also that it gets to corals in the ocean, helps with coloration, develops colorful pigments that act as sunscreen, true coloration for some proteins, emittance at lower energy in the visible spectrum making more color and most proteins can use it for energy. Also, that some of the higher end panels have already added it and others are expected to join in. I would not be so quick to dismiss the importance of UV in the 350-400nm range. This is likely one of the real reasons why most LED panels are still behind T5 and MH in coloration. Nor do I care about an experiment where corals got UV alone... what good is this? I know that these corals that are nearly all collected on one breath get UV in the ocean just under the water... and assuming nature gets things right, until proven otherwise with scientific method, like any good scientist (and not that we have to prove that nature is right.. pseudoscience, which is too much reef science), then they have adapted/evolved to use UV as a resource available to them.

I think that it is important for people to know how to take your posts. Do you hobby, or are you an interested passer-by without any real experience with a reef tank like Oreo. Both can be helpful, but both also come from a different place and posts need to be weighed accordingly, although the passer-by seems to nearly always think that they don't need to experience what they are typing.

Agree 100 percent..

 

[TheGreatWave]

You got the wrong guy with the porosity or thin skeleton thing. That is not me who is on that one. I am not arguing that one at all.

The glass shield removes the harmful UVB and any UVC (if any, which it does not appear that there is). The UVA still gets through... you can see this in any chart, but you probably knew this too and also that it gets to corals in the ocean, helps with coloration, develops colorful pigments that act as sunscreen, true coloration for some proteins, emittance at lower energy in the visible spectrum making more color and most proteins can use it for energy. Also, that some of the higher end panels have already added it and others are expected to join in. I would not be so quick to dismiss the importance of UV in the 350-400nm range. This is likely one of the real reasons why most LED panels are still behind T5 and MH in coloration. Nor do I care about an experiment where corals got UV alone... what good is this? I know that these corals that are nearly all collected on one breath get UV in the ocean just under the water... and assuming nature gets things right, until proven otherwise with scientific method, like any good scientist (and not that we have to prove that nature is right.. pseudoscience, which is too much reef science), then they have adapted/evolved to use UV as a resource available to them.

I think that it is important for people to know how to take your posts. Do you hobby, or are you an interested passer-by without any real experience with a reef tank like Oreo. Both can be helpful, but both also come from a different place and posts need to be weighed accordingly, although the passer-by seems to nearly always think that they don't need to experience what they are typing.

It's more a matter of getting a tangible feel for it's importance. It's about 10% of the visible spectrum to begin with. While reds and greens get filtered due to wavelength, we also know at some point microwaves are absorbed by water too, especially with salt and nitrate.

I'm not sure how we ended up with UV good vs bad, we started out with UV is not mutually exclusive to MH as a response to MH being superior because of having some UV. T5 has a bit of UV and so does my Radion and even my old Kessil had a UV diode.