SPS tank: Light intensity vs. total PAR?

[shelburn61]

I am trying to choose between a 2x400w or 175w,250w, 175w setup. (2x400w Ushio 14k vs 2x175w Iwasaki 25k, 250w Phoenix)

If we assume total PAR would be the same with either setup, would I see any benefit from running the higher intensity bulbs?

[MCsaxmaster]

<a href=showthread.php?s=&postid=12402419#post12402419 target=_blank>Originally posted</a> by shelburn61
I am trying to choose between a 2x400w or 175w,250w, 175w setup. (2x400w Ushio 14k vs 2x175w Iwasaki 25k, 250w Phoenix)

If we assume total PAR would be the same with either setup, would I see any benefit from running the higher intensity bulbs?

This question doesn't make sense. PAR IS a measure of light intensity. PAR = photosynthetically active radiation. It is the intensity of light at 400 - 700 nm, measured as umol quanta/m2/s.

Chris

[JNye]

i would go with the 3 bulb set-up, i know the iwasakis have great par, plus with less watts, heat, wider coverage and overlapping bulb spectrums it offers more options. the only downside is the extra bulb at replacement time. Unless we can say that the 400s a definetively better for coral health, and thats doubtful considering so many people do great with 250s and 175s.

[reef / aholic]

. Light intensity - (LUX)
. Colour temperature - (Kelvin)
. Spectral range of light from 400nm to 700nm - (PAR)

[glassbox-design]

I believe what he's asking is power vs. spread...the total par will be about equal with the two set ups, but the 400's will over greater peak intensities in certain areas while the 175/250 set up will provide a more even light distribution over the entire tank.

It's a tough question to answer without the tanks dimensions and reflectors used.

I am curious, why mix in the Pheonix? Why not run 3x175 saki 15K's?

[JCTewks]

<a href=showthread.php?s=&postid=12403758#post12403758 target=_blank>Originally posted</a> by MCsaxmaster
This question doesn't make sense. PAR IS a measure of light intensity. PAR = photosynthetically active radiation. It is the intensity of light at 400 - 700 nm, measured as umol quanta/m2/s.

Chris

Not to be a stickler...but I thought that PAR = Photosynthetically Available Raditon?

[PSam]

I have seen "active" used more often than "available.

I don't really understand the question either.

[JCTewks]

I could DEFINITELY be wrong on this, but it would be good to know :lol:

[shelburn61]

<a href=showthread.php?s=&postid=12410742#post12410742 target=_blank>Originally posted</a> by glassbox-design
I believe what he's asking is power vs. spread...the total par will be about equal with the two set ups, but the 400's will over greater peak intensities in certain areas while the 175/250 set up will provide a more even light distribution over the entire tank.

It's a tough question to answer without the tanks dimensions and reflectors used.

I am curious, why mix in the Pheonix? Why not run 3x175 saki 15K's?

Pretty much. I'll be running lumenarc minis in either setup over a 48x24x24. My rockwork is setup in 2 islands so I'm not really worried about spread so much. My bulb choices are based on color and efficiency - the phoenix is to add a bit more blue to the sakis

<a href=showthread.php?s=&postid=12403758#post12403758 target=_blank>Originally posted</a> by MCsaxmaster
This question doesn't make sense. PAR IS a measure of light intensity. PAR = photosynthetically active radiation. It is the intensity of light at 400 - 700 nm, measured as umol quanta/m2/s.

Chris

my understanding is that light from a single, very intense light source penetrates deeper than from multiple, less intense sources. If so 1 PAR unit is not necessarily equal to the next...

[wld1783]

Be careful about using low K bulbs. The same green stag under a reeflux 12K will be brown under an iwasaki 65K. trust me I'm using a 65K on my grow out sump.

Some folks drop huge $ on overdriving de 20K radiums to bring out the colour. Their tanks do look great.

Personally I'd go with 2 400 watt 12K Reeflux bulbs on lumanarc reflectors. I have these and you have the best balance between colour and PAR. Here's the link http://reefdepot.net/bulbs.html

Bill

[shelburn61]

<a href=showthread.php?s=&postid=12421250#post12421250 target=_blank>Originally posted</a> by wld1783
Be careful about using low K bulbs. The same green stag under a reeflux 12K will be brown under an iwasaki 65K. trust me I'm using a 65K on my grow out sump.

Some folks drop huge $ on overdriving de 20K radiums to bring out the colour. Their tanks do look great.

Personally I'd go with 2 400 watt 12K Reeflux bulbs on lumanarc reflectors. I have these and you have the best balance between colour and PAR. Here's the link http://reefdepot.net/bulbs.html

Bill

I prefer the ushio to the reeflux, but bulb choice is not really the issue here. I'm trying to understand whether I will see any benefit from the higher peak intensity of the 400w bulbs...

[MCsaxmaster]

<a href=showthread.php?s=&postid=12420902#post12420902 target=_blank>Originally posted</a> by shelburn61
my understanding is that light from a single, very intense light source penetrates deeper than from multiple, less intense sources.

Kinda sorta, without reflectors, but the use of reflectors seriously complicates the calculation. With good reflectors most of the light can be put in the tank where we want it, instead of everywhere else, regardless of the light source.

<a href=showthread.php?s=&postid=12420902#post12420902 target=_blank>Originally posted</a> by shelburn61
If so 1 PAR unit is not necessarily equal to the next...

Huh-uh. PAR is a measure of intensity. 1 unit of PAR is 1 unit of PAR. It's kind of like the riddle, "Which is heavier, 100 lbs of bricks or 100 lbs of feathers?" They weigh the same, of course.

If two light sources provide equivalent PAR they are, by definition, providing equivalent intensity. However, different light sources do not provide the same intensity. Some lights are brighter than others.

[jglackin]

I am interested in these discussions, as I really don't know #&#* about it. I have a Solaris LED lighting system that puts out PAR equivalent to MH, but the light that is in my tank is not nearly as intense. When people with MH come see my set up, that is the first thing that they notice. Because the light does not spill out of the tank and light up the room like MH does, it gives the appearance that the Solaris does not put out as much light. There is a great deal of debate about this. What I do know is that, if I take a SPS from a tank with MH and place it high in my tank under the Solaris, I stand a good chance of bleaching it. I usually have to place it lower and then work it up the water column.

[MCsaxmaster]

<a href=showthread.php?s=&postid=12427396#post12427396 target=_blank>Originally posted</a> by jglackin
I am interested in these discussions, as I really don't know #&#* about it. I have a Solaris LED lighting system that puts out PAR equivalent to MH, but the light that is in my tank is not nearly as intense.

Again, that’d be like saying 100 lbs of bricks weighs more than 100 lbs of feathers ;) PAR IS a measure of light intensity.

<a href=showthread.php?s=&postid=12427396#post12427396 target=_blank>Originally posted</a> by jglackin
When people with MH come see my set up, that is the first thing that they notice. Because the light does not spill out of the tank and light up the room like MH does, it gives the appearance that the Solaris does not put out as much light.

That’s a good thing though—the light goes into the tank, not into the room, saving energy. The corals don’t care how much light comes off the light, they only care how much light makes it to them. If the light goes into the room, it’s useless. LED fixtures like these can have intensity similar to lower wattage metal halides.

<a href=showthread.php?s=&postid=12427396#post12427396 target=_blank>Originally posted</a> by jglackin
There is a great deal of debate about this. What I do know is that, if I take a SPS from a tank with MH and place it high in my tank under the Solaris, I stand a good chance of bleaching it. I usually have to place it lower and then work it up the water column.

Yeah, one can get pretty respectable intensity out of them :D

Chris

[wld1783]

I prefer the ushio to the reeflux, but bulb choice is not really the issue here. I'm trying to understand whether I will see any benefit from the higher peak intensity of the 400w bulbs...

Ushio's are nice I've seen many good SPS tanks using them.

Outside of theory I look at experience and results... Based on numerous tanks including RK Tanks of the month, the best tanks have high intensity 400 or 250 watt lighting. Remember corals in the wild can trap and consume much more food than we can provide in our reef tanks. However we can compensate by using high intensity lighting. This is just opinion as I've never seen a nice SPS tank with weak lights...If anyone has one please speak up...

Id definantly would go with the 2X400 watt ushios.

Bill

[jglackin]

<a href=showthread.php?s=&postid=12428085#post12428085 target=_blank>Originally posted</a> by MCsaxmaster
Again, that’d be like saying 100 lbs of bricks weighs more than 100 lbs of feathers ;) PAR IS a measure of light intensity.

Not necessarily. It depends on how someone is using the word "intense" or at least it depends on what the person is intending the word to mean. My Solaris is supposed to put out the same PAR as a 400 watt MH, but a MH puts out far more visible (intense to my eyes) light.

[MCsaxmaster]

<a href=showthread.php?s=&postid=12429495#post12429495 target=_blank>Originally posted</a> by jglackin
Not necessarily. It depends on how someone is using the word "intense" or at least it depends on what the person is intending the word to mean. My Solaris is supposed to put out the same PAR as a 400 watt MH, but a MH puts out far more visible (intense to my eyes) light.

But that's an example of why we can't use our eyes to judge light intensity ;)

Our pupils will dialate and contract as appropriate depending on ambient light. If you turn a metal halide lamp on inside, it will be blindingly bright, and you won't be able to stare at it...or at least you shouldn't :cool:

If you take the same light outside and turn it on, it will barely look like it's on. You can stare right at it because your pupil has contracted sufficiently.

Our eyes are just a terrible judge of absolute light intensity--they're only ok for relative intensity in a given environment. The only thing that works is to measure light intensity, so that 1 lb of brick = 1 lb of feathers ;)

Chris

[shelburn61]

<a href=showthread.php?s=&postid=12425216#post12425216 target=_blank>Originally posted</a> by MCsaxmaster
Kinda sorta, without reflectors, but the use of reflectors seriously complicates the calculation. With good reflectors most of the light can be put in the tank where we want it, instead of everywhere else, regardless of the light source.


Huh-uh. PAR is a measure of intensity. 1 unit of PAR is 1 unit of PAR. It's kind of like the riddle, "Which is heavier, 100 lbs of bricks or 100 lbs of feathers?" They weigh the same, of course.

If two light sources provide equivalent PAR they are, by definition, providing equivalent intensity. However, different light sources do not provide the same intensity. Some lights are brighter than others.

Sax,
I know what PAR is - a manmade unit of measurement the definition of which corals don't give a shiznit about. Why do you insist on trying to point out my statements are wrong without addressing the question?

Will 2 bulbs with higher relative outputs produce different results than 3 bulbs with lower outputs? (Assuming same 4'x2'x2' tank and same total PAR from each lighting system)

Does 1lb of feathers equal 1lb of bricks when it has to travel through 2 ft of saltwater to the bottom of a fishtank?

[MCsaxmaster]

<a href=showthread.php?s=&postid=12430503#post12430503 target=_blank>Originally posted</a> by shelburn61
Sax,
I know what PAR is - a manmade unit of measurement the definition of which corals don't give a shiznit about. Why do you insist on trying to point out my statements are wrong without addressing the question?

But please understand, I’m trying to clear up a misconception that would prevent you from appreciating any sort of answer. My concern is that you have a better understanding of the topic, and can therefore make a good decision. Doing so is impossible if the very premises on which the question is based are mistaken.

<a href=showthread.php?s=&postid=12430503#post12430503 target=_blank>Originally posted</a> by shelburn61
Will 2 bulbs with higher relative outputs produce different results than 3 bulbs with lower outputs? (Assuming same 4'x2'x2' tank and same total PAR from each lighting system)

Possibly since you’d have 2 vs. 3 intensity “hotspots” in the tank, one beneath each bulb. You wouldn’t have the same amount of light coming from these various systems though. Different arrangements will give you different amounts of light.

<a href=showthread.php?s=&postid=12430503#post12430503 target=_blank>Originally posted</a> by shelburn61
Does 1lb of feathers equal 1lb of bricks when it has to travel through 2 ft of saltwater to the bottom of a fishtank?

Ha, this is an interesting question. With good reflectors you should be able to get similar rates of light extinction using different light sources. The determining factor for the light intensity you get at depth, then, will be the intensity of the light at the source. In other words, if you compare the intensity at 24” to that at 6” it might be 10%. If one light source gives you 1500 umol photons/m2/s at 6” and another gives you 800 umol photons/m2/s you’ll have 150 and 80 umol photons/m2/s from each, respectively.

Chris

[shelburn61]

<a href=showthread.php?s=&postid=12430627#post12430627 target=_blank>Originally posted</a> by MCsaxmaster


Ha, this is an interesting question. With good reflectors you should be able to get similar rates of light extinction using different light sources. The determining factor for the light intensity you get at depth, then, will be the intensity of the light at the source. In other words, if you compare the intensity at 24” to that at 6” it might be 10%. If one light source gives you 1500 umol photons/m2/s at 6” and another gives you 800 umol photons/m2/s you’ll have 150 and 80 umol photons/m2/s from each, respectively.

Chris

This is what I was trying to confirm. So a single light source with higher peak intensity is better at "pushing" light to the bottom of the tank...

[MCsaxmaster]

<a href=showthread.php?s=&postid=12433032#post12433032 target=_blank>Originally posted</a> by shelburn61
This is what I was trying to confirm. So a single light source with higher peak intensity is better at "pushing" light to the bottom of the tank...

It isn't better at "pushing" light to the bottom per se, it is simply brighter. A brighter light will be brighter than a dimmer light at any given distance from the bulb (assuming similar reflector/light extinction).