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.

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.

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.

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.

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

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

^^^ 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

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.

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

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

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.

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

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.

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.

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.

Sweetness... thanks man!

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?

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

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.

Mispost*

*BUMP*

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

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?

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.

that is true, sort of, the reason they lose par value is the electrodes inside the lamp splatter a bit on start-up in the start-up. small amounts of the electrode coat the inside of the envelope and sort of tint the glass. this is one of the main advantages of a good e-ballast, they fire in as few as 2-3 cycles, as apposed to magnetic which take around 40 cycles to fire

halides do create more UV which encourages the corals to produce more pigments which are the colors we like to see


the one point, and it is actually 2 fold, that I would take issue with is a matter of efficiency, which translates to heat and electric bill.

in short, halides will give you more light for less money. that is to say they are more efficient. they produce less total BTU per lumen and require less watts per lumen. what this means is that if you ant to achieve the SAME PAR VALUE with T-5, the T-5 setup will require more watts and produce more heat than a metal halide setup producing the SAME par value. this is not true with 20k halide lamps





6500 +VHO actenics

Hello folks... n00b here with a question...

Some recently history: I have a BC29 with a stock hood. I am looking to get MH and did some research on here and found lots of people who mod a $10 300w hallogen lamp from Walmart into their hoods. So, I have two 70w MH ballasts from ballastwise on the way. Now I am looking for cheap bulbs on e-bay - if this idea doesn't work out I don't want to have spent tons of $$$ - but all the 70w bulbs I find are HQI. Is there a difference in ballast and/or lamp that would run those? In other words, can I run an HQI bulb on a regular MH lamp and MH ballast or does it need its own HQI lamp & ballast?

Thanks for the help guys!

HQI is METAL HALIDE

Not totally sure what you are asking...but heres a stab.
Metal halides come in 2 type of bulbs. (for aquarium purposes)
1.HQI...is a double ended smaller bulb (latchs by spring ends)...known to put off less heat then MG
2.MG...or mogul ended bulb...single end that screws in. Little hotter bulb.

Both bulbs come in different wattages and Kelvins.
Your ballast should support the exact wattage bulb...this usually makes it HQI or MG.
Then you just need the appropriate retro hood and connectors.
Hope this helps.

Izzue

Thanks guys! Yes, your answers help a lot... an HQI is just another name for MH and does not require a different type of ballast and/or lamp.

This is a very broad statement. This thread is about MH and MH is a great lighting source but how can you say T5 will require more watts, more heat and produce less par in all situations? What t5 lighting setup are you referring to? What bulb types?

T5 has so many options that a blanket statement like this is entirely false. I currently have 432w of T5 over my 120g. There is a crocea in my sandbed and I have been able to grow colorful zoas and sps in all depths of my tank. Can you light a 120g with under 500w of mh and see the results I have... not possible, as you would need at least 2 250w hqi bulbs and some actinic supplements to achieve the desired coloration. My tank increases 0 degrees when the lights are on (no mh system can say that), the heat may be there but with t5 you can easily blow the heat away so there is little to no transfer to the tank.

When it comes to par, if you had 432w (8 bulbs) of 6.5k ge T5 bulbs over a 120g tank you would have so much par that you literally could keep 0 corals because they would all bleach and die; the tank would be a tad yellow though I also paid $440 for my 4 retro kits... definitely cheaper than any MH options I could find.

Bottom line, MH is a great choice in many circumstances but lets try to avoid blanket statements like the quoted one above as it is obviously not true.

do SE bulbs need a glass shield like DE bulbs?

No they do not.

I have done DIY conversion on Hardware store MH flood light, appears no difference except the bulb kelvin.

I used a single end medium socket (normal household socket) bulb 70W MH fixture, swap put the bulb into a 70W 6500K Iwasaki medium base Aquarium MH bulb (Can be hard to find). It runs perfect for the past 5 years. But for the 70W, unless it's is HQI (Which you can convert as well from Halogen fixture as covered by other's threads) you can not get higher kelvin than 6500K bulbs.

Recently, my newest MH DIY is from 10,000K Automotive HID MH light,
for details check out my 4G Pico W 35W Metal halide thread.
http://www.nano-reef.com/forums/index.php?...p;#entry1415752

it is simple math and physics




sure 3 x 150, depending on kelvin you would have 20-100% more par



well here is a blanket statement that is not true, let's try to avoid those

Lets add this up, 3 x 150 = 450.... my t5 system has 432w, since 432 is less than 450 I guess math is on my side. Now with physics you have to get fairly complicated and figure out how much energy is lost to heat, lost in the wiring, lost in the ballast, lost to any other non-usable energy source, etc. and all this energy loss would have to be compared to what energy is usable by our corals (which is a huge debate in and of itself).... so lets just not go there. So physics smysics is about as honest of a debate as you can have as to which lighting source is better. There are so many variables that NO one has honestly considered them all.

So I believe you need to retake both math and physics



If you could get 20-100% more par (which is a huge range and I suspect you just made that up on the fly ) with MH, than why is T5 so popular? Because people are bored and T5 sounds like such a cool name... yeah thats probably why

So lets think of the best 450w MH system for par... what would it be iwasakis??? or maybe something else, it really doesn't matter. But lets consider my option of 8x54w 6.5k ge... again with this setup you could not keep a single photosynthetic coral in a 120g tank... the corals would simply fry. Under the MH system I know you could keep a wide variety of corals no matter what the kelvin rating of the bulbs because the 150w would simply not penetrate to the bottom of the tank. But with either system going for just par would look extremely ugly and yellow.



You started the blanket statements... I chose mine more carefully, if I made them at all to begin with.

Can you find a MH system that does not have to deal with heat issues? Mh most often requires either a chiller or a massive set of fans complimented with a fair amount of top-off to replace evaporation. I only top off 2x as much in my 120g with T5 compared to my 18g with MH; now lets ask another math question... 120g is how much bigger than an 18g??? a bit more than 2x that is for certain.

But I do get off topic here don't I? Lets answer those MH questions and keep T5 out of it.

oh I will have to look up the specs on current draw and par value, sanjay's site is great for that and you can get rated current draw for that... tell me you are kidding about a 18 watt disparity.. and lamps verry a lot. if you want to make a big stink about it, sure i will go dig all this up for you monday




you are more than welcome to come over and see mine any time i am available. i run 2 250MH 8" off the water 14 hrs a day I have a jbj 1/10 chiller which rarely runs and probably do not need it, yes i have a 8" fan on my sump temp controlled and it runs about 1/2 the time in the day and 1/4 of the time at night. the halides each have a 2" fan on them it is a 100 gallon tank my evap is ~ 1 gallon a day, I refill a 5 gallon bottle of lime water every 4 days or so

it is a serious invite, I love showing it off

I am going to jump in here about the whole evaporation issue. Sometimes evaporation has nothing to do with lighting or heat at all. I was evaporating about 1.5-2 liters a day a few months ago in my current setup. I made a change in the return pump from the fuge, I went with more GPH and now evaporate twice as much. This was apparent overnight not in weeks. It started evaporating up to 3 liters a day. I haven't changed anything else. I am running a 250 watt MH. So lighting and heat are not the only factors in evap.

Very true, many other issues can cause an increase/decrease in evap... surface area of the water exposed to air, ambient temp of your house, etc. Honestly though most tanks with MH need to deal with heat in some way and that is just a fact. Whether you just have a chiller for backup or an extra set of fans ready to turn on when/if necessary. If you have a MH system and you are not prepared for the extra heat (especially in the summer) you have a very high chance of frying your tank. Since this thread is about answering MH questions I feel it is very appropriate to address this heat issue especially since in a nano your temp can spike in a hurry. I know... I almost killed my tank when I first put on my 250w MH over my nano. I hit 90 degrees before I even knew what happened. Luckily a simple large room fan was all that was needed to keep it under control.

I'd love to come see your tank, as visiting other setups is always interesting to me. I'm constantly amazed at the variety of setups in this hobby and you can have success in a wide variety of ways. You don't by any chance live in UT? If not I'll have to take a rain check and ask that you post pics of your setup... do you have a thread showing your tank? I'd really like to see it.

I never did start a thread on the display tank, i should, I have done a lot of cool things to it.. completly ot, but IMO, giant return pumps and skimmer pumps are the worst offender when it comes to heating a tank

my brother lives in sandy ut, I get out there every few years, are you anywhere neer sandy?

I am going to set up a custom DIY 29 gallon and want some assistance on lighting i was thinking of going with 2 T5 actinics and one MH the problem is I do not know anything about MHs and want to know the best wattage.

It depends what you are trying to keep, but I would think that a 150w DE or 175w SE setup would do the job just fine in your case. If you intend to keep very demanding SPS low in the tank, you might consider going with 250w, but even then, I think you would be fine with 150-175w. Since you are using actinics, I would suggest going for a lower-kelvin MH bulb, 6500-10,000k. Generally speaking, you get more PAR per watt with such bulbs. One exception to this is the Iwasaki 175w 14k bulb. It is a very high-PAR bulb with a nice bluish-white color, and is arguably the 'best' bulb available in this wattage range.

If you are planning on keeping LPS and softies, then I wouldn't worry so much about PAR, as they just aren't as demanding in the light category, generally speaking. Of course, there are exceptions.

Avoid the XM 15k 150w bulb at all costs. It is, bar none, the absolute worst MH bulb I have ever seen. It is so low on PAR that some 70w bulbs put out more usable light. Corals wither under it. I wouldn't use those bulbs to jam old food into my garbage disposal, as it would be an insult to the old food. I find the low quality of that particular bulb to be especially odd, as their 10k and 20k bulbs are good bulbs, and come highly reccomended.

So, the short answer: go for 150-175w, avoid the XM 15k 150w bulbs.

- Josh

I have the aquapod 24 150 Halide. I got a clam the other day and was planning on placing it on rock higher in the tank so it gets more light. The second day I had it it attached it self to the rock. The next morning it kept jumping off the rock. Everytime I move it up it will jump again. Should I just keep it low (where it keeps jumping to)? The bulb is a year old but I will be replacing it shortly. Also on ebay I found the correct bulb I need for like $20. Does anyone know much about these?

What brand bulb are referring to? Cheap bulbs on ebay are just that, cheap. Lots of options for 150w mh bulbs, just figure out what kind of bulbs will run on your particular ballast.

What is your experience?

OMG

I just read this ENTIRE thread and you're telling me it stops HERE?

haha

I just switched from the stock BC hood to a 150w Sunpod. From what I'm reading here... if I'm understanding it correctly...


If I went with a 6500k 150 HQI bulb, and supplemented my lights with say some form of PC Actinics, I would

A. Avoid that yellowish look that nobody (including myself) seems to like
B. Give it the crisper clean (mildly blue-ish) look that everyone seems to like with something like the Phoenix 14k
C. My corals would reap the benefits of the 6500k bulb and would actually grow better than with a 14k?

In my stock BC hood that's on my wifes tank, the guy at the store dropped it and busted the 10k bulb that comes with them, and tucked in a 8k (if memory serves me) bulb. Very yellow with it on by itself, but the Actinic bulb really brings the light to a nice bright (slightly blue) level.

I have no experiences with those cheap bulbs over ebay. Knock off bulbs that may not hold spectrum or may not even fire for that matter. I just dont want anyone wasting there money, There should be lots of threads on RC maybe even a few here explaining just why those bulbs are poor choices.

Wow, my thread is still around. Nice to see its helping people

whats your thoughts on lighting for my 40 breeder (see signature) which will be mostly SPS.
2 250's se
2 175's se
both will have actinic vho 4 bulbs on a new IC660

^^^????^^^
lol