RBuddha

Your Metal Halide Questions Answered

252 posts in this topic

For those of you that are new to reefing and the list of lighting options out there, I wanted to post a thread about Metal Halide since thats probably the most talked about lighting option out there. Im not trying to play this thread off as me being some kind of Metal Halide guru, but I do see questions come through here that can easily be answered. So in an effort to consolidate all the info into one post I'm offering my knowledge. Any other veteran halide users are free to add any info that can help out when understanding Metal Halide.

 

What IS Metal Halide?

Metal Halide was produced for mostly commerical use much like Mercury lamps. It fires a charge passing an electric arc through a mixture of gases that ignite producing light. I wont get into the whole technical side of how it works because frankly, its boring and if you really need to know that then there are other resources that can explain it a lot better than i can.

 

So why should I use Halide instead of Fluorescent lights?

Metal Halide is the closest you can get to natural sunlight. While Fluorescent lights are coming close to doing the same thing, metal halide really is the best type of lighting for a hobbyist that wants to keep a large variety of corals. As present Fluorescent T5 High Outputs are coming close to doing just as well as Metal Halide so that is another option if you dont mind losing the shimmer effect of Halide. In the near future when LED lighting is perfected and the prices come in line with affordability, it could make halide and fluorescent obsolete.

 

I'm worried about my electric bill and using Metal Halide.

I hear this often and it is a big concern among people setting up a new tank or switch from fluorescent to halide. Keep in mind that if you are running a small reef the increase is minimal and you wont see a huge spike in your electric bill. If you stick with electronic ballasts they are by far more efficient than the old magnetic ballasts.

 

Can I buy a halide bulb and just wire up a socket for it?

No. Metal Halide requires a ballast to fire. You CANNOT wire it directly into 120v and just fire it up. Generally electronic ballasts are more efficient and run cooler than older magnetic ballasts.

 

So whats all this SE and DE stuff?

SE= Single Ended bulb. This is the same type of bulb you see in your house with a threaded end that screws into a mogul base. DE= Double Ended bulb. This is a bulb that is connected at both ends in which the current is fired into the bulb. Generally speaking and from a hobbyist point of view DE bulbs are more efficient than SE bulbs since they are fired from both ends and dont lose energy from the threaded connection.

 

This all sounds great but I hear Halide puts out a lot of heat.

This is true. Halide produces more heat than any other bulb. So much in fact that you cannot put plastic or acrylic as a shield between the bulb and water, it WILL melt or deform it. Halide can increase the temperature of a tank and cause evaporation issues if you're using a large amount of power. You'll see most people hanging it with pendants above the water to reduce the heat and to also not burn the corals by being too close to the water. In most enclosures there are fans to cool the bulb and keep the heat out of the tank but in most cases you'll still see a small increase in temeperature if you're using a lot of halide.

 

Ok, so i'm ready to buy a bulb but what's this 10k, 14k and 20k stuff?

These are ratings on the PAR which is the Lumens and "color" of the bulb if you will. 10k is the closest emulation too natural sunlight. As the lumens go up in value e.g. 14k you see more of a blue coloration. For more info with pretty pictures check out this link: http://www.cnidarianreef.com/lamps.cfm

 

 

Someone told me metal halide puts out radiation. Is this true?

Yes it is true but its in such small amounts that it wont have any effect on you or your tank if you use glass. Most glass has a UV rating of some sort so you dont have to search all over for glass shops that sell it. When I first started i called around like an idiot asking for UV glass and everytime i got the same answer, "All glass has a uv rating". Always use a glass covering over halide and dont stare at the bulb unless you like your eyes burned out of your head.

 

How long do these halide bulbs last?

Halides should be replaced at least every 8 months. This is a conservative estimate and depending on your light cycle and manufacturer of the bulb, it can last much longer.

 

Someone told me that i should use halide and actinic supplementation, is this good?

In my opinion, halide + actinic is the best combination to get natural sunlight emulation as well as actinic supplementation for an overall nice look for a tank. Granted, some will argue that you can just use a 14k bulb and call it a day. Really its personal choice but either way they are both great for your tank.

 

What is the shimmer effect people talk about with halide?

Metal Halide is "Source Point" lighting meaning that the source of light is coming from a single point as opposed to light spread over a large area like fluorescents produce. You can get an example of the shimmer effect by holding a flashlight over your tank pointing at the sand. You will need some surface agitation from a powerhead or pump to get the best effect. The shimmer effect adds a more natural appearance to your tank and is similar to what youd actually see if you were in the ocean looking at corals.

 

When dealing with Metal Halide bulbs always remember to never touch the bulb with your hands. The natural oils from your finger will contaminate the glass and cause heat to gather in that area and effects the bulb. If you happen to touch it just remember to clean off any finger prints or marks and use a paper towel or tissue provided with the bulb to handle it. This is more of a problem with DE bulbs since they can take some amount of force to put into a DE fixture. As with anything reef related be careful and dont be afraid to ask questions. The learning curve is steep and most people here are more than willing to offer advice and any help they can.

Edited by RBuddha

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This is a great idea for a thread and I think it should be stickied both here and in the Beginner's forum. Actually I was considering doing something similar for T5s, cleanup crews and hitchhikers.

 

P.S. Pictures are worth 1,000 words.

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metal halide really is the best type of lighting for a hobbyist that wants to keep a large variety of corals.
That's really the only statement I think doesn't belong; MH vs. T5HO is largely personal preference at this stage, I don't think there's enough information out there to be able to definitively say one is truly better than the other as far as the end results are concerned.

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I think you may be right seeing as how T5 HO's are creeping up on metal halide but i think their time will be limited and all lighting might soon be replaced with LED + Actinics.

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Good job, RBuddha, but I was alwas told to replace my bulbs every 12-14 months? 8 months is more for something like PCS.

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That could be true but it would depend on your lighting cycle and quality of the bulb. 8 months is a conservative suggestion.

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^^^ Sup Flatlander.

I actually had a pretty knowledgable LFS owner tell me a couple of months ago...MH bulbs dont need replacement until they burn out????

He said hes checked par rating as the bulb ages...yes the par output decreases...but not enough to be a factor to change the bulb.

I have nothing to back this... Just FYI

 

Izzue

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Yea, I just changed my bulbs because I thought I was 'supposed to' after a year or so. Of course, I do not really have anything in my tank that needs such a high PAR, but maybe you will see a bigger difference with acro's and such.

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Well this thread is pretty timely. I just changed today from a 15K XM to a 10K ReefOptics, and the color difference is annoying. I'm thinking about just getting a 14K. Right now I have a mag ballast (all of my lighting stuff except the bulb is second hand) and a crappy-but-functional pendant that holds my mogul bulb. The pendant is just long enough to hold the bulb and maybe 5 inches wide. I don't think I have enough room in there to wire in some actinics (do they even make them that small?). Does anyone have a suggestion about what I should do to get more of a white color? The blue on the 15 was too blue, but it was at least more colorful than the yellow-green tint I have with this 10K. I want to see the natural colors of my stuff!

 

TIA

-j

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How do you know it's time to replace a DE MH bulb; I have two 150 watt 20K bulbs and have had them for over 1 year.

 

They still fire up and my corals appear okay, does anyone have any feedback?

 

Thanks

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How much more of a benifit does electronic give you over magnetic ballast?

 

The LFS owner says he think the magnetic ballast put out a better light color. I know the electronics are cheaper to run and cooler but by how much? Is it that obvious?

 

I am thinking of buying a used 175w HQI retro fit from him for 125, he has been using it for 2 years, magnetic ballast, with an stale old bulb 14m.

Edited by el_vulture619

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OK, I have a question. I have 70 watt MH plugged into a power center outlet which is plugged into the wall. On the other side of the room, I have a window ac. Whenever the ac goes on, the MH fixture turns off and in about 10 minutes it comes back on. I talked to an engineer at work and he said it is a wiring problem for the wall outlets. But the light is the only thing that loses power, the pumps and skimmers and other power compact lights stay on. So is it a wiring problem or do I need a special equipment connected to MH fixture to prevent this?

 

Thanks

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well, it sounds like everything is flickering, but the MH bulb (because it has to warm back up) is the only thing you're noticing that turns off.

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How much more of a benifit does electronic give you over magnetic ballast?

 

The LFS owner says he think the magnetic ballast put out a better light color. I know the electronics are cheaper to run and cooler but by how much? Is it that obvious?

 

I am thinking of buying a used 175w HQI retro fit from him for 125, he has been using it for 2 years, magnetic ballast, with an stale old bulb 14m.

 

A 175W bulb is not an HQI. Magnetic ballasts don't really put out better light color, but they do make some bulbs look a little different, which may or may not be better. You can buy a new electronic 175W retro for $125 from hellolights.com . You can also buy a new 175W retro with a magnetic ballast for $75-100 from the same place. You'll have to order a new bulb anyway so who cares about that.

 

Electronic really is the way to go though. I'd also suggest just going with a 150W HQI instead of a 175W mogul because the bulb selection is better, and 175W moguls tend to have a difficult shape that doesn't work well over smaller tanks. Most of the 175W reflectors are too wide to work over a 12" wide tank.

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This was a great thread. The only thing that I am not sure of and didn't see in this thread was what would be the right size buld for certain ranges of tanks. I am looking of putting together a halide system for my 10 gallon reef that I am about to throw together.

 

So what size bulb should I get?! Lots to choose from!

 

Thanks

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This was a great thread. The only thing that I am not sure of and didn't see in this thread was what would be the right size buld for certain ranges of tanks. I am looking of putting together a halide system for my 10 gallon reef that I am about to throw together.

 

So what size bulb should I get?! Lots to choose from!

 

Thanks

 

70W or 150W

 

imo, 70/150 is good for 16 or less inches. 250W is good for 16 to 24". The more SPS you want, the more likely you'll be able to use a more powerful bulb. A 150W would work on an 18" tall tank if you kept sps near the top, and lower light coral near the bottom. Anything closer to 24" would be better with 250W if you want higher light coral.

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70W or 150W

 

imo, 70/150 is good for 16 or less inches. 250W is good for 16 to 24". The more SPS you want, the more likely you'll be able to use a more powerful bulb. A 150W would work on an 18" tall tank if you kept sps near the top, and lower light coral near the bottom. Anything closer to 24" would be better with 250W if you want higher light coral.

 

 

Sweetness... thanks man!

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what is the differecne between MH and HQI?, i have 150w. HQI and on the box it says in put out twice as much as 250w . Metal Halides and runs cooloer.

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what is the differecne between MH and HQI?, i have 150w. HQI and on the box it says in put out twice as much as 250w . Metal Halides and runs cooloer.

 

 

lol... is that the sunpod 150w?

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i found the differce.. HQI is a type of MH.. its a halogen quartz bulb. .. and yes sunpod

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I'm thinking of adding a MH fixture to my 20gal long tank. Currently I'm running a 30" CF light, but I'd like to add clams and SPS to the tank.

 

I'm wondering what the difference is between a MH fixture you buy from a fish store and one bought from a hardware store. I do know that the hardware store fixtures are MUCH MUCH cheaper.

 

If anyone has had personal experience with building their own fixture using a MH bought from a hardware store, please let me know what your experience has been.

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Mispost*

Edited by maverikv

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*BUMP*

 

I would like to know the answer to this too. Thanks!

 

I'm thinking of adding a MH fixture to my 20gal long tank. Currently I'm running a 30" CF light, but I'd like to add clams and SPS to the tank.

 

I'm wondering what the difference is between a MH fixture you buy from a fish store and one bought from a hardware store. I do know that the hardware store fixtures are MUCH MUCH cheaper.

 

If anyone has had personal experience with building their own fixture using a MH bought from a hardware store, please let me know what your experience has been.

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I have a little problem with my 175W mh. I got a 10k bulb for my 5k today, but since i put the 10k in, it's flickering... problem with bulb or ballast?

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I probably missed it but what K is best for SPS coral growth? I currently running 150Watt 14,000K Phoenix bulb. I have a bunch of SPS now and growth is pretty SLOW.

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