Explain Metal halide please

laserjim · 05/30/2008, 05:26 PM

Why is it that if I put pc lights over my tank it light the whole tank very bright and when I use metal halide it looks as though there are shadowed areas that shimmer and nowhere near as bright? Is this normal ? The Halides are dimmer yet they are better light?

oceanparadise1 · 05/30/2008, 05:37 PM

need more info what kind of set up are u using? how many mh, what wattage how many pcs what wattage, but it should not matter much the mh are MUCH better then pcs

laserjim · 05/30/2008, 05:44 PM

Just an observation, my Solana with t5 4x24 is at least twice as bright as my 150 hqi. And yes the bulb is fine I went to the fish store and its the same way. It must be a different type of light,more direct.

Colin · 05/31/2008, 07:29 AM

Halides are a point source of light (like the sun), versus tubes which are a line source of light (like, um, a fluorescent light). Tubes's fill in the shadows because they stretch across the tank. MH's shimmer because of the shadows caused by ripples on the tank's surface (just like the sun and the ocean). The shimmer is actually one of the best things about MH's.

Normally you'd want a MH bulb every 2 feet in order to light sufficiently and cut down on dark spots.

HTH,

--Colin

ganjero · 05/31/2008, 09:23 AM

it also has to do with lummens, sometimes T5s and PC are able to produce more lummens per what than MH ( specially 70w and 150w). But lummens are not important for reefing. Lummens are a measure of visible light to the human eye, what you are looking for is high PAR values which is whats important for photosynthetic organisms, and MH normally produces higher PAR values and penetrates the water deeper.

SulfurAcid · 05/31/2008, 10:07 AM

MH and T5 combos are very common, as they have the amazing light and high PAR that is associated with Metal Halides, and the light-filling and low temp characteristics of T5s.

On my 90, I have 3 250watt Metal Halides and 4 48" T5s, no dark spots, but I have that shimmering, the SPS and everything else loves it.

hahnmeister · 05/31/2008, 10:32 AM

Quote:

Originally posted by ganjero
it also has to do with lummens, sometimes T5s and PC are able to produce more lummens per what than MH ( specially 70w and 150w). But lummens are not important for reefing. Lummens are a measure of visible light to the human eye, what you are looking for is high PAR values which is whats important for photosynthetic organisms, and MH normally produces higher PAR values and penetrates the water deeper.

Not true actually.

Halides produce the most lumens per watt, as well as the most PAR/watt. A 3000K halide tops out at about 105 lumens/watt, and PC tops out at about 60, with T5 topping out at about 85/90 (HO/NO). The advantage of many phosphor based bulbs now (but not all), is that they maintain more of their output over time while halides tend to die rather fast in comparison. Also, phosphor based bulbs tend to be much more efficient at conversion to blue/actinic light than halide, so from that standpoint, T5s could have a higher output than halide. Personally, I think its a wash. But PC isnt even in the same boat. The phosphors degrade and shift rather fast, so your PC's often only last 9 months at best, while T5s can easily go 2x as long and do great.

Paulairduck · 05/31/2008, 01:35 PM

Quote:

Originally posted by hahnmeister
Not true actually.

Halides produce the most lumens per watt, as well as the most PAR/watt. A 3000K halide tops out at about 105 lumens/watt, and PC tops out at about 60, with T5 topping out at about 85/90 (HO/NO). The advantage of many phosphor based bulbs now (but not all), is that they maintain more of their output over time while halides tend to die rather fast in comparison. Also, phosphor based bulbs tend to be much more efficient at conversion to blue/actinic light than halide, so from that standpoint, T5s could have a higher output than halide. Personally, I think its a wash. But PC isnt even in the same boat. The phosphors degrade and shift rather fast, so your PC's often only last 9 months at best, while T5s can easily go 2x as long and do great.

learn something new everyday

laserjim · 05/31/2008, 01:49 PM

Yes, thanks everybody.

ganjero · 05/31/2008, 04:31 PM

Quote:

Originally posted by hahnmeister
Not true actually.

Halides produce the most lumens per watt, as well as the most PAR/watt. A 3000K halide tops out at about 105 lumens/watt, and PC tops out at about 60, with T5 topping out at about 85/90 (HO/NO). The advantage of many phosphor based bulbs now (but not all), is that they maintain more of their output over time while halides tend to die rather fast in comparison. Also, phosphor based bulbs tend to be much more efficient at conversion to blue/actinic light than halide, so from that standpoint, T5s could have a higher output than halide. Personally, I think its a wash. But PC isnt even in the same boat. The phosphors degrade and shift rather fast, so your PC's often only last 9 months at best, while T5s can easily go 2x as long and do great.

You always use the extremes, who uses 3000K halides for reefing? there are articles on lighting websites that show T5s HO put out more lummens per watt (about 90 per watt while a 400w MH puts something like 80 per watt).

hahnmeister · 05/31/2008, 05:36 PM

Using extremes is the best way to define the boundaries for discussion, and no, I dont always use them.

3000K bulbs happen to be the color that those bulb ratings get published in, so thats why I am using them. I could have just as easily used 6500K which most makers also publish, but you dont see 10,000K and 20,000K comparisons for two reasons: 1. as you get bluer, the lux is not an accurate means of comparison since it doesnt read the bluer spectrums fairly... as you go bluer in spectrum, the lux will drop faster than the PAR. 2. Blue light energy is of higher frequency, so it also takes more energy to produce... if you want to compare 'best possible' of those technologies, you are going to compare a 3000K, which is also the most commonly used indoor light. The PAR/watt of bluer T5s and halides is always a fraction of the daylight bulbs.

Some of those lighting websites you are reading are no doubt proponents of T5 lighting. The actual rating for some HQI spec bulbs is over 100, at about 105. The rating of T5 NO is in the 90 range, but T5HO is actually lower... 85 range at best. Their are claims and speculation though that over the course of a T5's life and the course of a halides life, that the T5 will maintain its output longer however. I have yet to verify this myself. Otherwise, you are right, 400 watt probe-start halides are not very efficient... its the HQI's that are. Most makers of T5 units will use this number because its lower of course, and because in the US we still like our cheap M59 ballasts for our HID lighting. But HQI is the best halide has to offer.

The real problem was the claim that PC was better somehow... that just isnt so in any way.

But it is highly possible that as we go bluer, yes, T5s may be the more efficient bulb. I am getting that impression from my own tank testing. As you go from 3000K to 6500K, the drop in T5s is minimal, and a blue+ style bulb maintains a great deal of the output that a daylight bulb has, not to mention the 'dayactinic' bunch. Dont quote me on an exact number or something (Id have to recheck my notes and data), but a T5 seems to maintain at least 60% of its output as you go from 3000K to 20,000K. A halide, well... starts to take it in the pants just going from 3000K to 6500K, and then again from 6500K to 10,000K, and then to 20,000K. A 20,000K halide is lucky to produce 1/4 the light that a 3000K does. So even without actual lumen/watt or PAR/watt ratings, the relative efficiencies can be extrapolated from the point readings that have been taken of various T5 and halide bulbs. All you have to know is the lumen/watt efficiency of one bulb that you can also take the PAR/watt point reading of and convert the rest (a GE 3000K is a perfect example). So if you are into a 'deep blue' look, then yes, I would suggest T5s over 20,000K halides. But if you are into any look that uses 10,000Kish bulbs (even halide + T5), then halides can still maintain their advantage from their higher output in the warmer spectrums. Thats why I say its a wash. Phosphor based bulbs are really UV at the core (a UV-C bulb is a clear tube version of a PC, T5, etc). This UV is what excites the phosphors and converts it to whatever spectrum is desired for output.... so the T5s have a certain advantage in that they are starting out at that end of the spectrum in the first place, so for blue light... less energy is lost in the conversion.... or so it seems.

DarG · 05/31/2008, 07:39 PM

maybe I missed it but I dont think anyone addressed what reflector the OP is using for his halide.

A Lumenmax reflector (or LA, or Reef Optix etc) over a 2 ft X 2 ft area is going to look very, very uniformly lit.

A single cheap, tiny halide reflector over a 4 foot long tanK (or even over that same 2 foot square with some of these tint reflectors) is going to create an intense hot spot centered under the bulb and then shaded areas as the are extends beyond the center of the lamp.

IOW ... a properly applied halide system with quality relfectors is not going to create the shaded areas or shadows that the OP reports.

Unless the OP is talking about the contantly moving shaded areas or "shimmer lines" as we call them ...

Fuzznutz · 05/31/2008, 08:13 PM

Quote:

Originally posted by DarG
maybe I missed it but I dont think anyone addressed what reflector the OP is using for his halide.

A Lumenmax reflector (or LA, or Reef Optix etc) over a 2 ft X 2 ft area is going to look very, very uniformly lit.

A single cheap, tiny halide reflector over a 4 foot long tanK (or even over that same 2 foot square with some of these tint reflectors) is going to create an intense hot spot centered under the bulb and then shaded areas as the are extends beyond the center of the lamp.

IOW ... a properly applied halide system with quality relfectors is not going to create the shaded areas or shadows that the OP reports.

Unless the OP is talking about the contantly moving shaded areas or "shimmer lines" as we call them ...

Not to mention ballast and kelvin. So many variables with MH lighting. Excellent posts Hahn and Dar

Esquare · 06/01/2008, 06:43 PM

Uhhhhhh light good.....dark bad.

Esquare · 06/01/2008, 06:45 PM

Sorry, couldn't help myself. Ya'll just flew so far over my head all I could see were the contrails.

05/30/2008, 05:26 PM	#1
laserjim Another Day In Paradise Join Date: Nov 2006 Posts: 1,956	Explain Metal halide please Why is it that if I put pc lights over my tank it light the whole tank very bright and when I use metal halide it looks as though there are shadowed areas that shimmer and nowhere near as bright? Is this normal ? The Halides are dimmer yet they are better light? __________________ Jim Current Tank Info: 430 gallon, 4 radion gen 3pro, 4 T5 bulbs, 60 inch Life Reef skimmer, Apex gold, 2 Dos dosers, ,80 gallon sump. 2 Cor pumps. 2 Ecotech MP 60 powerheads

05/30/2008, 05:44 PM	#3
laserjim Another Day In Paradise Join Date: Nov 2006 Posts: 1,956	Just an observation, my Solana with t5 4x24 is at least twice as bright as my 150 hqi. And yes the bulb is fine I went to the fish store and its the same way. It must be a different type of light,more direct. __________________ Jim Current Tank Info: 430 gallon, 4 radion gen 3pro, 4 T5 bulbs, 60 inch Life Reef skimmer, Apex gold, 2 Dos dosers, ,80 gallon sump. 2 Cor pumps. 2 Ecotech MP 60 powerheads

05/31/2008, 01:49 PM	#9
laserjim Another Day In Paradise Join Date: Nov 2006 Posts: 1,956	Yes, thanks everybody. __________________ Jim Current Tank Info: 430 gallon, 4 radion gen 3pro, 4 T5 bulbs, 60 inch Life Reef skimmer, Apex gold, 2 Dos dosers, ,80 gallon sump. 2 Cor pumps. 2 Ecotech MP 60 powerheads

06/01/2008, 06:43 PM	#14
Esquare Registered Member Join Date: Jan 2008 Location: Lorain, Ohio Posts: 1,954	Uhhhhhh light good.....dark bad. __________________ Eddie Current Tank Info: 40 Breeder with Dwarf Lionfish

06/01/2008, 06:45 PM	#15
Esquare Registered Member Join Date: Jan 2008 Location: Lorain, Ohio Posts: 1,954	Sorry, couldn't help myself. Ya'll just flew so far over my head all I could see were the contrails. __________________ Eddie Current Tank Info: 40 Breeder with Dwarf Lionfish

05/30/2008, 05:37 PM	#2
oceanparadise1 Moved On Join Date: May 2008 Location: Rochester,NY Posts: 2,925	need more info what kind of set up are u using? how many mh, what wattage how many pcs what wattage, but it should not matter much the mh are MUCH better then pcs

05/31/2008, 07:29 AM	#4
Colin Registered Member Join Date: May 2000 Location: Oklahoma City Posts: 848	Halides are a point source of light (like the sun), versus tubes which are a line source of light (like, um, a fluorescent light). Tubes's fill in the shadows because they stretch across the tank. MH's shimmer because of the shadows caused by ripples on the tank's surface (just like the sun and the ocean). The shimmer is actually one of the best things about MH's. Normally you'd want a MH bulb every 2 feet in order to light sufficiently and cut down on dark spots. HTH, --Colin

05/31/2008, 09:23 AM	#5
ganjero saiperchémibatteilcorazon Join Date: Sep 2005 Location: Clearwater, FL Posts: 4,027	it also has to do with lummens, sometimes T5s and PC are able to produce more lummens per what than MH ( specially 70w and 150w). But lummens are not important for reefing. Lummens are a measure of visible light to the human eye, what you are looking for is high PAR values which is whats important for photosynthetic organisms, and MH normally produces higher PAR values and penetrates the water deeper.

05/31/2008, 10:07 AM	#6
SulfurAcid Registered Member Join Date: May 2008 Location: Miami, FL Posts: 120	MH and T5 combos are very common, as they have the amazing light and high PAR that is associated with Metal Halides, and the light-filling and low temp characteristics of T5s. On my 90, I have 3 250watt Metal Halides and 4 48" T5s, no dark spots, but I have that shimmering, the SPS and everything else loves it.

05/31/2008, 05:36 PM	#11
hahnmeister Moved On Join Date: Sep 2005 Location: Brew City, WI Posts: 10,156	Using extremes is the best way to define the boundaries for discussion, and no, I dont always use them. 3000K bulbs happen to be the color that those bulb ratings get published in, so thats why I am using them. I could have just as easily used 6500K which most makers also publish, but you dont see 10,000K and 20,000K comparisons for two reasons: 1. as you get bluer, the lux is not an accurate means of comparison since it doesnt read the bluer spectrums fairly... as you go bluer in spectrum, the lux will drop faster than the PAR. 2. Blue light energy is of higher frequency, so it also takes more energy to produce... if you want to compare 'best possible' of those technologies, you are going to compare a 3000K, which is also the most commonly used indoor light. The PAR/watt of bluer T5s and halides is always a fraction of the daylight bulbs. Some of those lighting websites you are reading are no doubt proponents of T5 lighting. The actual rating for some HQI spec bulbs is over 100, at about 105. The rating of T5 NO is in the 90 range, but T5HO is actually lower... 85 range at best. Their are claims and speculation though that over the course of a T5's life and the course of a halides life, that the T5 will maintain its output longer however. I have yet to verify this myself. Otherwise, you are right, 400 watt probe-start halides are not very efficient... its the HQI's that are. Most makers of T5 units will use this number because its lower of course, and because in the US we still like our cheap M59 ballasts for our HID lighting. But HQI is the best halide has to offer. The real problem was the claim that PC was better somehow... that just isnt so in any way. But it is highly possible that as we go bluer, yes, T5s may be the more efficient bulb. I am getting that impression from my own tank testing. As you go from 3000K to 6500K, the drop in T5s is minimal, and a blue+ style bulb maintains a great deal of the output that a daylight bulb has, not to mention the 'dayactinic' bunch. Dont quote me on an exact number or something (Id have to recheck my notes and data), but a T5 seems to maintain at least 60% of its output as you go from 3000K to 20,000K. A halide, well... starts to take it in the pants just going from 3000K to 6500K, and then again from 6500K to 10,000K, and then to 20,000K. A 20,000K halide is lucky to produce 1/4 the light that a 3000K does. So even without actual lumen/watt or PAR/watt ratings, the relative efficiencies can be extrapolated from the point readings that have been taken of various T5 and halide bulbs. All you have to know is the lumen/watt efficiency of one bulb that you can also take the PAR/watt point reading of and convert the rest (a GE 3000K is a perfect example). So if you are into a 'deep blue' look, then yes, I would suggest T5s over 20,000K halides. But if you are into any look that uses 10,000Kish bulbs (even halide + T5), then halides can still maintain their advantage from their higher output in the warmer spectrums. Thats why I say its a wash. Phosphor based bulbs are really UV at the core (a UV-C bulb is a clear tube version of a PC, T5, etc). This UV is what excites the phosphors and converts it to whatever spectrum is desired for output.... so the T5s have a certain advantage in that they are starting out at that end of the spectrum in the first place, so for blue light... less energy is lost in the conversion.... or so it seems.

05/31/2008, 07:39 PM	#12
DarG Registered Member Join Date: Dec 2006 Posts: 5,515	maybe I missed it but I dont think anyone addressed what reflector the OP is using for his halide. A Lumenmax reflector (or LA, or Reef Optix etc) over a 2 ft X 2 ft area is going to look very, very uniformly lit. A single cheap, tiny halide reflector over a 4 foot long tanK (or even over that same 2 foot square with some of these tint reflectors) is going to create an intense hot spot centered under the bulb and then shaded areas as the are extends beyond the center of the lamp. IOW ... a properly applied halide system with quality relfectors is not going to create the shaded areas or shadows that the OP reports. Unless the OP is talking about the contantly moving shaded areas or "shimmer lines" as we call them ...