New Metal Halide Lamps? 7/12/09
Hi crew,
<Debi.>
I have a light fixture that has three metal halide lamps that need to be replaced due to age. The current lamp are 150w 10,000k and my aquarium maintenance fellow had suggested to go up to 14,000k in order to make it more blue. I agreed to that but when I went to get the bulbs he was out of the 14,000k and then said well go ahead and go to 20,000k, it will just be a little bluer and that is the only difference. I am hesitant to go with these as 10,000k more seems a lot different.
<They are quite different, both in color and usable light provided for your corals. The 20000K provide much less.>
My question is whether I should be able to see an appreciable difference between the 14,000k and the 20,000k bulbs?
<Yes, assuming the bulbs are correctly rated for color. Many are not.>
Which is more desirable in terms of natural looking light for a reef aquarium.
<It depends on your personal preference. "Natural" depends on when, where and how deep you are looking!>
My tank is 150 gallons, six foot long and about 18 inches deep. The light fixture holds eight T5 fluorescents and three metal halide lamps. Lots of light there!
<Hmm, yes. You could get away with the 20000K and a 4-6 10000K T5s, with the balance being actinic.>
I have to make a quick decision on this as the maintenance guy is coming in a couple of days to make the change.
<Do take a look at this site: http://www.manhattanreefs.com/lighting.
Sanjay Joshi has tested many of the common halide bulbs for many specs. Of which are the usable light for your corals (PPFD) actual color (CCT). Do note that if a bulb has a CCT of 0 it generally means it was so blue as to be off the scale of his meter.>
Thanks for all your help,
Debi
<Welcome, Scott V.>

Re: New Metal Halide Lamps? 7/13/09
Thanks for your very speedy reply, but if you don't mind I have a point of clarification.
<Sure.>
I went to the website you suggested and aside from it being pretty much over my head in terms of lighting standards it also does not address the particular bulbs I am being offered.
<Yes, not all bulbs are covered.>
The bulbs I am considering are SPS Metal Halide 20,000K double ended.
<Okay.>
I am afraid I misled you to an extent by not elaborating on my fixture set up. It does have eight T5's, they are all at this time Actinics, I believe they are called Super Actinic.
<That is a lot of actinic! You probably have a fairly blue appearing tank already.>
So with that in mind I would have those plus the three 20,000K halides. No white lights at all. Do I need to have some white lights?
<They do provide more usable light to the corals.>
I went to several aquarium stores today and looked at their show tanks, I am in Dallas so that isn't too difficult. Anyway, I don't seem to mind the bluishness of the 20k however, there was one that was very purple and it had no white lights at all.
<20000K's with 8 actinics will probably look similar to this.>
They said that their was just a lot of Coralline Algae in there and that was making it look more purple, but now I am concerned that I should add some white if I go with these halides that are so blue.
I do enjoy the more restful look of the bluishness, not sure that's word, but want to avoid the purple. Your original answer seemed to assume that I had all white T5's. So with this new information what would you think.
<I would be hesitant to go with 20000K in this setup. Some people like the very
blue look. I do not, it sounds as though you don't either.>
Thanks again so much for your help. Refilling this fixture is quite an investment so I am trying not to have "buyer's remorse".
<Understood and welcome.>
Debi
<Scott V.>

Metal Halide lamp application/Reef Lighting 5/21/09
Hello WWM crew,
<Hi Matt>
I have recently set up a Marine aquarium. It is a 75 gallon tank with a external sump, 175W MH lamp and a Sea Clone protein skimmer. In the sump I have some red tipped hermit crabs, live sand (bag from LFS) and a few small pieces of LR. I have crushed coral/shells and live sand and LR in the main tank. The live rock had been stored for a few years and I understand it is now dead rock but is still beautiful and give the tank inhabitants lots of good places to hide and explore. I cycled the tank with a few Domino Damsels and it has been up and running since late March (around 8 wks).
Nitrite is 0, PH is 8.4 and Nitrates are around 20-30 ppm. I am trying to get nitrates down by cutting back on feeding a bit, will do another water change soon.
<Your protein skimmer is not efficient enough for your size tank. Getting a quality efficient skimmer will go a long way in lowering nitrates and provide much better water quality for the anemones.>
Current I have 2 Dominoes, a few blue Damselfish with yellow tails, a shrimp, Horseshoe Crab, 2 convict worms, a clown and 2 Condylactis Anemones.  I have been reading as much as I can about the anemones and they are doing
OK, but I think they need more attention.
<Anemones are not easy to keep for any length of time.>
My utmost concern right now is the lighting, I am using a 175W MH lamp which is an industrial ceiling lamp that came out of a factory. It has a large dome reflector which sits nicely across the top of tank and I have tempered glass between the tank and bulb. The water temperature is stable around 78' when the lamp is on. I do have a submersible heater for the tank.  I believe it is 300w, but can't remember right now, it was listed for a 75gallon tank though. Back to the lamp. I did some research and found the lamp puts out 14000 lumens when new. I am not sure of the spectrum though. The lamp was hanging about 18" off the top of the water yesterday and this morning I rested it directly over top the right side of the tank and the anemones seem to be responding to it a lot better. The are currently getting larger and larger, the best I have seen them since I bought them. All the other creatures seem to be in great health. I understand I should buy more appropriate/better lamps as soon as possible but do you think the anemones have a decent chance of survival with this set up?
<If your MH fixture has the original lamp, the Kelvin temperature won't be close to what the anemones require. I'm guessing the Kelvin temp of your lamp is somewhere around 4500. A Kelvin temperature of 6500 or higher would be more suitable.>
With the exception of some new fully cured live rock from my LFS, I do not intend on adding any other creatures for several months, maybe a year.
<Matt, do read here and related articles.
http://www.wetwebmedia.com/marlgtganthony.htm>
Regards,
Matt in Newark, OH, USA.
<Cheers, James (Salty Dog) in Michigan>

Question About Lighting Spectrum 4/19/09
Hi Crew,
<Matt.>
I have a hopefully not too dumb of a question about lighting spectrum. I am building a 800 gallon (120" x 44" x 36") in wall reef tank and I'm weighing my options on lighting.
<Wow, big tank!>
The tank will be about 30 inches deep to the top of the sand. I am planning on 36 inches tall with a 6 inch deep sand bed.
The tank will have sps corals. I don't know if 2 48" 8 bulb T5HO fixtures will be enough for a tank this deep. What is your opinion?
<Well, it depends on where you intend to place the corals. If you want some on the bottom I would go with 10+ bulbs or MH.>
Of course, metal halide is an option, but worried about heat and power consumption. Would I need 250 watt MH or more?
<250s will do it.>
Now, the spectrum I want is 14,000K because of the corals and inverts. I was looking at the Lights of America Fluorex fixtures (the 100 watt fixture) but I don't want the 6500K bulb spectrum of these fixtures. First, would it be possible to make a diy filter (possibly blue tinted acrylic) to alter the spectrum, or would I still essentially have 6500K wavelengths that just look blue to the eye.
<Hmm, it effectively would change the spectrum by filtering out the red end of the spectrum.
You do end up with less usable light for your corals.>
I have had the best luck with coral coloration and algae control with 14,000K bulbs. With the cheaper fixture costs and operating expenses, I could use more of the Fluorex fixtures, possible supplemented with actinics. Please give me your opinion/advice on what is the best lighting route to go for this size tank.
<I am not much of an advocate for MH these days, but in this case I would go with four 250 metal halides.
There is little that will be frugal about running an 800 gallon reef!>
Thank you for all you do, I use your site often. Matt
<Thank you and welcome, Scott V.>

Replacement 150W Halide Bulbs 4/10/09
Hi crew,
<Hello Steve.>
It's been a while since I've posted a question but I am overdue a replacement to my halide bulbs and would appreciate some help.
<Sure.>
I'm clear on the replacement procedure (raise the lights, lower the duration etc..) I have a arcadia series 3, 3 x 150 halide unit over my 150 gal mixed tank (my system can be found here http://www.youtube.com/watch?v=O5Z4iJJ71oE). I'm currently on 14,000K bulbs which I find a little blue (but can live with if necessary), I know this topic has been covered many time before and that there is no one correct answer, but before I replace with arcadia bulbs (possibly dropping to 10,000K) wanted to ask if from a colour spectrum and manufacture perspective you had any suggestions on brand and model ?
<A few, the Aqualine Buschke being my personal favorite for the 150's. Check out Sanjay Joshi's site
http://www.manhattanreefs.com/lighting
Just put in 150 and leave the rest of the fields blank and it will give you a chart giving the values of all the different bulbs he has tested. Both usable light (PPFD) and the actual spectrum of the bulb (CCT).>
I only keep soft corals and am aware that even with a 6" DSB I still have 24" of water.
<Wow, deep tank.>
Thanks in advance and regards.
Steve Heath
<Welcome, happy reefing. Scott V.>

Re: Lighting Question, MH fixt., lamps    2/13/09
Ok, I am at it again with the questions. I think I want two MH pendants to hang over my tank. My tank is at about 78 deg consistently summer and winter with not much fluctuation at all. Here is a website I have found.
http://www.fishneedit.com/metal-halide.html . They have 70 watt MH pendants for $110 and 150 watt MH pendants for $130. I have done some searching for reviews on these and have read more good than bad about them.
<I tried doing a bit of research on FishNeedIt products and did not come up with much useful information. Most buyers of FishNeedIt products use their T5 fixtures and seem to be relatively happy with them. However, I am
skeptical of their MH reflector design and bulb selection as these are the two most important factors in a lighting set up.>
If you feel these are ok to pull the trigger on, which wattage would be the best for my tank? I would like to keep mostly soft and LPS corals and maybe some SPS corals but no clams or anything like that. Do you think 2 150 watt or 2 70 watt would be best?
<Since there is not much technical detail available for FishNeedIt's MH set ups, I would suggest for you to contact the manufacturer for more information (ballast, reflector and bulb specs) and recommendation.
However, from my experience, 70W MH is relatively weak especially for taller tanks and the bulb selection is quite small compared to the 150W counterpart.>
Also, they let you pick your bulb color. I was thinking for MH that 14000K would be pretty good. Any suggestions on this would be great.
<14k should be a good common ground between the white and sometimes yellow look of a 10k and over saturated blue look of a 20k. However, keep in mind that the "Kelvin" scale is not uniform between all these bulb manufacturers and are often times arbitrary. Some 14k bulbs are whiter and some are bluer than others. It is best to ask for a white balanced picture of the bulb in operation from the manufacturer.
I know that reef lighting can be a confusing subject particularly when there's a lot of misinformation floating around. That's why I always refer reefers to the work of Sanjay Joshi
(http://www.manhattanreefs.com/lighting). If you spend some time getting familiar with his site and read his articles, you will find your decision making process a lot clearer.>
Thanks again
Matt
<You're welcome. Cheers, Minh Huynh.>

Updating MH bulb   1/7/09
Hi,
<Hello Tina, Minh at your service.>
I have asked the crew a bunch of questions in the last year about my 90g tank and your replies were always helpful. Personally I think you guys & gals do a great job at solving problems in tanks that you really only have the most basic knowledge of, amazing! I had problems last year with nitrates too high, using a bad water filter, and a Rena filter going out. I have gone back to only using my r/o water filter, eliminating the Rena, getting 1 Hydor 3 & 2 Hydor 1. My nitrates are now at 2.5 and the diatom algae reduced by 1/2.
<Congratulations on successfully lowering the nitrate in your aquarium.>
But I am still getting a lot of small bushy clumps of very green algae, not sure if it is good or not. I have a Current SunPod 250 14000K HQI light.
My tank is a 90 g. 36"Lx24"Hx24"D. I thought the bulb was supposed to last 2 years but recently I noticed the light doesn't look as blue as it did when new. I researched your site & realized that the bulb needs changing, possibly contributing to the algae.
<All bulbs degrade over time and some degrade much faster than others. For example, a Radium bulb may expire after 6 months, a Phoenix bulb may last 12 months while a Radium bulb can last a whopping 18 months. A bulb's life expectancy varies depending on the bulb's construction and the type of ballast that drives it.>
I have sold all my LPS corals & am going to Birdsnest & SPS corals of similar lighting needs. I was wondering if I should replace the bulb with the Hamilton 14000K bulb it came with or should I consider changing the MFG & K rating of the double ended bulb? I find it rather confusing which bulb to pick since everyone says their bulbs are the best.
<Lighting selection is a very confusing subject but fortunately, there is a cheat available. A fellow aquarist, Sanjay Yoshi, has tested the majority of the available metal halide bulbs in the hobby and published all the performance data on his website: http://www.manhattanreefs.com/lighting.
If you take some time to learn how to operate the site, it should make your bulb selection decision much easier. Furthermore, I'd like to offer a suggestion for a particular bulb that has a great reputation in the hobby.
This is the Phoenix 14k bulb and it strikes the best balance between performance, longevity and efficiency. It is also the only bulb that has a longevity study done so you will know exactly when to replace it:
http://www.reefkeeping.com/issues/2007-04/ac/index.php.>
thanks for a great site!
Tina
<You're welcome. Cheers, Minh Huynh.>

MH Bulb will not fire 12/14/08
Hello
<Jay.>
I have been running metal halide lighting on my reef tank for 4 months. I have decided to replace my 14k bulb with a 20k bulb (both 400w). The new 20k wont fire.
<!>
The igniter tries to light it with an electric arc every 15 seconds or so, but the gas wont ignite.. I have tried it for 2-3 hours on end, but eventually, the igniter quits firing and its just dark. I have read about "break in periods" for new bulbs, but this one doesn't seem close to lighting. I re installed my 14k bulb and it lights instantly.
<Good.>
My ballast is a "reef fanatic" brand that my LFS sold me as a lightly used unit. I don't see any indication of a brand on the new bulb. I bought it from a local coral propagation company that uses these bulbs in their facility. Does it sound like a problem or should I keep trying to overcome this "break in period"?
<If the thing won't light at all one of two things are happening. Either the bulb is just flat out bad or it is pulse start, while the ballast you mention is probe start. Hard to know without knowing what the bulb is. Do you have a friend that may be able to try the bulb out for you, preferably with an electronic ballast?>
Thank you!!
Jay
<Welcome, Scott V.>

Re: MH Bulb will not fire 12/16/08 Wow! Thanks for the quick response...on a Sunday no less! <Heee, we are here all the time!> I contacted the guy I got the bulb from this morning and he is giving me the run-around that I probably have the wrong ballast for this bulb. <Or the wrong bulb for your ballast....a question a knowledgeable LFS would ask before selling a pulse start bulb in the US. They are not uncommon here, but the probe starts are much more common.> Told me that if I blew the bulb, I bought it. Let me just add that I wasn't shopping for a bulb, I was buying corals and the guy said he'd sell me a new 400w, 20k bulb for cheap, So I bought one. <Hmmm....> There was no discussion at this point what kind of ballast I had and what kind of bulb he was selling. The bulb was obviously new and in an unmarked, white box and it looked identical to the bulb I'd been using. Seemed like a good deal...(famous last words?). Anyway, I am including a picture of my ballast and the bulb. <Tis an electronic ballast, this should fire either type of bulb. Starting to suspect the reason for the deal.> I don't know if you can discern from the photos weather or not the two are compatible, but I am trying to gather a little more knowledge before I go try to return the bulb. <They are compatible, nothing you have done here has burned out the bulb. I suggest you make every attempt to return it.> Thank you very much! Jay <The illumination of your old bulb demonstrates the ballast is fine, the problem does indeed sit with the bulb. This is one side of the story, but one I have seen many times. It i possible the bulb was damaged between the LFS and your home, but not likely. The willingness of the LFS to work with you here will speak volumes. Scott V.>

Replacing MH bulbs 8/22 08
Hey y'all -- I went through the archives for a bit and found a lot of stuff about replacing fluorescents with MHs, but not much about this very simple question. I'm switching new bulbs for year-old bulbs on my 2x175w 10000K rig. Right now, I run my actinic PCs from 11 a.m. to 11 p.m. and my MHs from 1:30 p.m. to 9:00 p.m. Should I cut an hour off my MHs for 2 weeks or so to acclimate things (leathers and Zoanthids) to my new bulbs, then return to the normal schedule? Thanks!
Ed
<You could, I generally just swap the bulbs. Unless you wait way too long to switch bulbs there should not be a huge shift in intensity or spectrum. A year out of a 10000K bulb is not too much to ask. Some of the bluer bulbs will shift more in a shorter time and will need special care in switching or more frequent replacement. You will be fine. Welcome, Scott V.>

Metal Halide Bulbs Cracking – 08/21/08
I've had some trouble with metal halide HQI double-ended bulbs going out. They work for a few days and then won't light, and all the 'gas' is gone from inside the bulb.
<<Unusual…have you contacted the manufacturer re?>>
I am extremely careful about inserting into the lamp holder, even using a flathead screwdriver and opening the holder to lower in the bulb and then tightening it back to the bulb (not too tight, just snug).
<<Okay…but do you touch the bulb envelope with your bare fingers? When the bulb heats up, oils/other contaminates from your skin can cause the bulb to crack>>
Still no success. There are tiny, or sometimes not so tiny, cracks in the bulb after only a few days.
Do you think this is an issue with the ballasts, or do you think replacing the lamp holders would solve this problem?
<<If you’re trying to drive 250w bulbs with 400w ballasts then yes, the ballast may be the problem. Misaligned bulb holders may also be the problem (placing sideways or torsion stress on the bulbs). If it’s not these, and you’re not handling with bare hands or otherwise mishandling the bulbs, then I suggest you turn to the manufacturer for answers/assistance…and maybe even consider switching>>
Thanks for the help.
<<Regards, EricR>> <Hope all don't mind terribly my kibitzing here: I encourage all to carefully clean and wipe MH, HQI, in fact, all lamps, on a "regular" basis... when they're turned off/cool, and going to be off a few minutes... to remove, prevent differentially cooled/heated areas on their glass surfaces. BobF>

2 quick questions... HQI lamp sel., Cyano consumers...  08/06/2008
Guys,
<<And Gals I hope...Andrew with you today>>
Thanks for all the help in the past with my questions. I was wondering what brand of HQI 250W 14K bulbs you recommend?
<<Regarding recommended HQI bulbs, a few good brands are Current USA, BlueLine and Iwasaki>>
Are there better ones that last longer or you think are better.
<<All the above mentioned manufactured bulbs I would happily recommend>>
And...........what, if any type of clean-up crew (crabs, snails) eat Cyanobacteria?
<<using a cleanup crew to tackle Cyano is not overly the best solution. All you would be doing in a control exercise, not a correcting one. Cyano needs light and nutrients to grow, also, come consider low flow a partial cause for Cyano. Fixing this at the root cause is your best option, and syphoning the Cyano out in the meantime while dealing with it. Please do read more on the bacteria and its methods of removal. http://www.wetwebmedia.com/bluegralgae.htm >>
Thanks, Jeromy
<<Thanks for the questions, hope this helps. A Nixon>>

MH lights, Bulb stress... . 6/25/08
Hello, I have a simple question (I think).
<Sounds good!>
I have a 3 light system of 250HQI bulbs, my question concerns power going off and the coming back on within a minute or less. Will this affect the bulb or fixture in any way? I recall from somewhere that if a MH light is turned off it should not be turned back on until bulb cools, but with power surges common in these days I know I must be mistaken.
<Well, the unfortunate truth is that this can cause stress on the bulb that may result in cracking; in my experience it isn't likely- a power out/return isn't going to do it, but the information is out there to keep people from shutting them off and turning them back on repeatedly- for water changes, reaching in the tank, kicks and giggles, etc.>
Thanks
<No problem>
Mike Winston
<Benjamin>

Broken Metal Halide Bulb 6/19/08
I have a metal halide fixture with 2 250watt HQI double ended bulbs and 4 50/50 power compact bulbs. I've had it for about 2 months or so and one day the left HQI bulb didn't fire, upon inspection it was cracked. So I replaced it and two days later the HQI bulb on the left side stopped firing and again was cracked, however this time the left side was attached to the other ballast.
<Yikes!>
I'm worried that something is wrong with the fixture, or that both ballasts are possibly faulty. These bulbs are expensive and I'd rather not go through a few more before I can isolate exactly what is wrong. I suppose its possible these could just be coincidental occurrences, but I'm hesitant to think that and put in another $60 bulb until I hear something back from you guys.
<Not too likely a coincidence.>
I did some Google searching this but wasn't able to get any good data regarding this situation. This question may be better sent to an electrician but I'm guessing you guys have lots of experience with these setups and I value your opinion. I look forward to hearing from you. Thanks.
<There are two likely culprits to this. First, if the bulbs get splashed while they are hot, this will cause them to crack. HQI’s almost always sit behind a glass shield, so it is likely the sockets are misaligned in the fixture. If one is twisted a bit out of alignment this puts stress on the bulb and can cause arcing. I have seen this kind of stress break quite a few bulbs. The fix is easy, just loosen the socket, put your bulb in, mark where it is at, take the bulb out and tighten the socket into place. Do not tighten it with the bulb in, if it twists you have potentially broken another bulb! Welcome, good luck with this, Scott V.>

MH Bulb Choice 6/10/08
Hey WWM crew,
<Hello Jason!>
Good morning! I have a tank that is clam dominated. Last count I was up to 24 clams.
<Wow, holy clams!>
I have T. Crocea, T. Maxima, T. Derasa, T. Squamosa, and I'm still on the hunt for T. Gigas & Hippopus.
<Have a big tank and calcium reactor?>
Its that time to change the MH bulbs. I’m currently running 3 250w MH with 14k bulbs. I’ve been thinking about several color combos.
I don’t want to use any VHOs, T5, etc. for supplemental lighting.
Here are a couple combo's I've thinking about. Can you give me some advice and tell me what combo you think would be the best.
1. (2) 10k with 14k in the middle
2. (2) 10k with 20k in the middle
3. (2) 14k with 10k in the middle
4. Or just stick with (3) 14k
Thanks for the help!
Jason
<This really comes down to personal preference. All 10000K bulbs will give you the best growth, but likely not a color you will like without actinics. The 20000K bulbs are too blue for my personal taste and do not provide much usable light when compared to the 10000K bulbs. The 14000K bulbs fall in the middle of course. Fact of it is, if you are happy with the 14000K bulbs, stick with them. If you want to experiment do buy one bulb first (or try out a friends, must be a good friend!) to see if you like the look. One thing I have seen time and time again is someone with a successful tank switching bulb spectrum to just end up going back to the old bulb type. We get used to a certain look and set it as the standard. One interesting, fun site is http://www.reeflightinginfo.arvixe.com/.
 This site gives you both the actual color of the bulb along with the PPFD, usable light from the bulb to your clams, and much other useful information as well. It just helps you make an informed decision not only on spectrum, but brand of bulbs to use. Welcome, have fun, Scott V.>

Re: MH Bulb Choice 6/11/08
Scott,
<Hey there Jason!>
Thanks for the info. Right now my tank is 4ft long x 2ft wide x 18 high, 20gal sump & a 35gal DIY refugium.
I'm actually in the process of getting my new clam tank built (8ft long x 4ft wide x 18inchs high), new sump (4ftx 2ftx 18in) and also a new big refugium.
<Wow, nice!>
As for calcium reactor I haven't used one yet. I've been topping off with lime water.
<Whatever works for you and your Ca hungry livestock.>
I test my water every Friday's and all my param.s are always stable and good. 20gal water changes are done every Friday religiously. I've had the tank up and running for about 1 year now and the clams have been in the tank well over 6 months. Once the new tank is ready I'll have more room to play with and I'll start picking up some more clams.
<I must admit I am quite jealous. Your system sounds great, clams are the personal favorite. A large clam tank is a dream of mine. But the wife says one huge system is enough and I can’t part with my other corals. Go figure.>
Thanks for all the great info! Have a great day..
Jason
<Welcome, enjoy the new system, Scott V.>

New Light Bulbs – 04/25/08
Hej Crew,
<<Goddag, Michael!>>
I am about to change my bulb for my 250 W metal halide lamp.
<<Okay>>
In doing so should I reduce the light hours?
<<Not in my opinion…best to maintain a “full” photoperiod>>
Should I reduce it from the current 8 hours to for instance 5 hours, and then gradually increase it over a couple of weeks?
<<Nope…better to lay a few layer of fiberglass window screen (or similar) over the top of the tank and remove a layer every three days. If such material is not available to you, try raising the height of the lamp(s) about 6” and the lower it a couple inches at a time (every three days) until you get back to the “normal” height>>
Thanks,
Michael Fick
Denmark
<<Happy to help. Eric Russell…South Carolina>>

Re: New Light Bulbs – 04/26/08
Hi Eric,
<<Hello Michael>>
Thanks for your reply.
<<Quite welcome, my friend>>
And you have learnt some Danish !!!! Det er godt!!!(That is good).
<<Ah well, the NET is a wonderful tool [grin]>>
Until the next time. Take care Eric.
<<Cheers, Eric Russell>>
P.S. The Linckia is still doing good (If you remember)
<<Ah yes…and excellent to hear. I do hope it continues to prosper. EricR>>

Halide Question 2-25-08
Hi Bob,
<Or Mike, as the case may be>
Hope you and the crew are fine.
<Biostatistics was canceled today, so today is a fine day!>
I have what I think is a short and sweet question. I have a 125 gallon long reef tank with all different types of corals, SPS, LPS, etc… I am currently running 15K bulbs. I was looking for a change for ascetic purposes only by going with 20K bulbs. Would it be OK to change all the bulbs at one time or would gradually change them every couple day. I have ( 3 ) 250 watt bulbs.
<Changing them all at once would be fine, because 20k is going to be less intense, rather than more. Remember, a higher Kelvin temperature will equate to less PAR, as a reminder>
Thanks in advance,
<Anytime>
Chris
<M. Maddox>

Are Home Center Metal Halide Bulbs Suitable For Reef Tanks? (Unfortunately…No) – 02/11/08
Hi Everyone,
<<Hello Robert>>
I know the LFS and online order stores make their money selling "fish specific" products...
<<Yes…>>
My question is, are the 250 watt Phillips metal halide bulbs I can get at my local Home Depot useable in my reef tank?
<<No…>>
They do not give a Kelvin rating on the box and I don't know if their light spectrum is of the proper intensity.
<<Mmm, intensity would be fine no doubt…but the Kelvin temperature will not be. These bulbs will typically have a Kelvin somewhere between 3000K and 4600K…neither suitable nor attractive. I can’t say why a 10000K bulb costs 3-4 times as much as a sub-6500K bulb. Perhaps a result of the “elements” used/required to achieve the higher color temperature…though I suspect “other” reasons. But the bottom line is that you will have to bite-the-bullet and pay for the “fish specific” product>>
Thanks,
Robert
<<Happy to share. EricR>>

HQI versus mogul Differences 1/24/08
Hello, Crew. I hope all is well with you.
<It is, hello Dan.>
I've been doing extensive research concerning MH lighting, specifically looking at double-ended (DE, HQI) versus single-ended (SE, mogul) bulbs and fixtures. I hereby proclaim myself "lost" and was wondering if you guys might be able to offer some bread crumbs leading me back to the trail.
<Sure.>
My main sources for information have been Reef Central forums, your FAQs, and then analytical data from Sanjay's site: http://www.reeflightinginfo.arvixe.com.
<Great site.>
Some things are clear: DE requires a glass shield while SE does not. Aside from this, I have heard many rumors/generalizations, and I have systematically invalidated them with Sanjay's data:
Generalization: DE are brighter than SE for the same wattage.
<Yes, but they do also consume more power.>
Result from data: Basically across the board, the SE bulbs have more PPFD than equivalent (same manufacturer, color temperature, and ballast) DE bulbs (using a shielded fixture on the DE). This is across manufacturers, ballasts, and wattages.
<This is something most do not pay attention to, you do generally come out ahead with an unshielded mogul than a shielded HQI.>
Generalization: SE bulbs are just DE bulbs with an extra shield and a different mount.
<From a user’s standpoint, yes. The HQI bulbs do fire different, hence the specialized ballasts for them.>
Result from data: The same bulb (same manufacturer, color temperature, wattage, and ballast) tends to have a very different spectrum in DE than than SE. For example, the SE XM 10K bulb has a huge blue spike that the DE does not.
<Yes, even thought they are manufactured by the same company, they are entirely different bulbs. You will also notice different spectra in the bulbs from ballast to ballast.>
Generalization: DE tends to be more "blue" than SE for the same bulb.
<With some manufacturers.>
Result from data: This is inconsistent but there are certainly specific cases (e.g. the XM 10K above) where the spectral data does not support this. There seems to be more correlation to ballast type (magnetic versus electronic) than bulb form factor.
<Hence your labeling generalizations.>
Another consideration is that the "better" reflectors, e.g. LumenArc III and LumenBright, are much more available for the SE bulbs. The former only has one fixture, the LumenArc Stealth, for DE bulbs, and the latter only accept SE bulbs. For SE bulbs there are many more sizes, etc.
<The HQI bulbs are becoming more and more popular, with commensurate increase in choices.>
Can you guys help me out here? What are your experiences? Ideally I'd like to do this (buying MH ballasts, bulbs, reflectors) once.
Thanks much!
Dan
<Dan, I have used many types and spectra of bulbs. I currently use mogul based bulbs for the reasons you listed above. They generally use less power, run bluer and yield more PPFD (unshielded). That is my choice, others may advocate for HQI, but both will work fine. Hope this helps you decide, Scott V.>

Impact of Switching from 20K to 10K Lamps
Reef Lighting 12/19/07
Crew,
I have a SPS dominated mixed reef system. I have been running 250 watt XM 20K single end bulbs supplemented by two URI Super Actinic 110 watt VHO bulbs for several years. The lighting runs on a HQI ballast. It is time to replace my MH bulbs.
I have been satisfied with the overall appearance and growth rate of my corals. The one area I would like to see improvement in my reds, purples and pinks. My reds, purple and pinks are not as bright and crisp as I would like. I am considering trying the 10K bulbs this cycle. I would not like the yellow hue I read about but thought that perhaps the actinic supplementation would overcome that issue.
<I've never saw a yellow hue with 10K lamps.>
Do have an opinion and/or a recommendation about this? It would seem I may address my objective, get even faster growth rates, and not have the yellow appearance I want to avoid. I like the blue aspects of my historical lighting but like the rest of you I am always looking to tweak appearance and performance.
If I make this change to a hotter lamp I assume I need to acclimate the corals for a period of time. Could I reduce the photoperiod and gradually increase it or do I need to diffuse the light at first?
I would appreciate your thoughts.
<I personally like the 14K lamps, just enough blue for good color. I use no supplemental lighting (actinics, etc). If you go with 10K's, along with using the actinics, you should get a pretty nice color combo. I've never witnessed any dramatic growth change in corals by switching Kelvin temperatures as long as the range lies between 10K-20K. The 20K lamps are too blue for my liking. As far as adjusting the photoperiod, do not believe this is necessary unless you were going to a higher wattage lamp, then I would consider doing so.>
Happy holidays,
<And to you. James (Salty Dog)>
Mike

Metal Halide Bulbs...Cheap Is Cheap! – 11/28/07
I have had my 15000k metal halide bulbs in use for about 10 months and it seems that the spectrum is getting more on the red side, especially on one of them.
<<Some spectral shift is expected...though quality bulbs should last a longer than this before the change would be visible to the “human” eye>>
The diatoms and red slime algae has been getting progressively worse and more so on the side with the redder bulb.
<<And likely more than “lighting” attributed to this. Do ensure water quality/water flow is up to par>>
I was wondering how long a metal halide bulb should last.
<<All metal halide bulbs will experience some spectral shift and loss of PAR over time...but there has been speculation/anecdotal proof that a quality manufactured bulb can remain useful for as long as two years. It’s also been surmised that the lower Kelvin-temperature bulbs remain “good” longer than the higher Kelvin-temperature bulbs. Then of course, there’s the Mogul vs. DE debate with the latter usually coming out on top in the “useful lifespan” argument as well. You should draw your own conclusions, but I tend to keep my Ushio made 10000K DE bulbs for 14-18 months before seeking replacement>>
Also, does the quality of the bulb vary from manufacturer to manufacturer, or are they all relatively the same in terms on quality and life expectancy.
<<There can be WIDE deviations in quality/life expectancy between manufacturers. Beware the “bargain basement” bulbs...I have heard tales of some real “crap” being offered>>
I only ask because there seems to be pretty dramatic price differences based on brand (i.e. $20/bulb on eBay vs. $65/bulb for Coralife).
<<Indeed... Discounts/sales can be found from time to time among the high-end bulb manufacturers...but more often than not, you get what you pay for>>
In terms of light acclimation, I was planning on cutting the photoperiod down 50% and gradually incrementing it back over the course of 7-10 days. Should this be adequate?
<<Not really, you need to temper the intensity (and not reduce the photo-period). I suggest the “fiberglass screen” method or if possible, increase the distance of the lights from the water’s surface and gradually lower over the course of 7-10 days. Please see here and among the links in blue for these and other strategies for lighting acclimation: http://www.wetwebmedia.com/acclimcrllgtfaqs.htm>>
Thanks guys!
<<Happy to assist. EricR>>

150W lighting  11/15/07
Greetings WWM crew!
<Hello Jeff and Lisa!>
I've used the search function and read through multiple questions on the use of 150w de bulbs, but felt I needed confirmation on my suspicions before I purchased a lighting system.
<Researching first will save much headache and money later.>
My tank is 48"x24"x 20" tall (shallow 100g). I'll probably go with a 1" crushed coral/sand bed for aesthetics (and likely a RDSB for nitrate control).
I'd like to keep Acropora in the top 1/3 of the tank, Montipora, Echinophyllia and Favites in the middle third and maybe a Galaxea and/or Fungia on the bottom.
My plan is to use 10000K 150w DE bulbs (hopefully retrofitted into mini Lumenarc reflectors) flanked on each side by 2- 54w T5s (2 actinics for
dusk-dawn, and 2 Blue plus). I'm also flirting with the idea of having the 150s on a light mover to provide subtle variations in the angle of the light.
I'm fairly certain that this config will be sufficient for the aforementioned livestock, but I wonder if it would be flexible enough to allow me to keep an anemone or possible a lower light requirement clam (like Squamosa or Deresa) if I developed a hankerin' ;)
<This lighting system will be fine for what you plan. It is more than sufficient to sustain these corals and even a clam as the water column will be less than 18" after displacement. An increase in photoperiod (time lights are on) will compensate for any shortcomings in PAR from the lower watt bulbs. Generally, 250w metal halides are the norm with PAR readings varying between 300PAR to 500PAR within the first 15" of the water's surface. Your lighting system will be producing between 250PAR-400PAR depending on which bulb you choose.
Bulb choices are mainly of aesthetics. 6500k lamps grow corals faster but look yellow. 10000k grow very well, but look white. 14000k and up look blue, have shorter bulb life, and do not offer the same growth rates. Because of your supplemental actinic lighting I would recommend a 10000k or 6500k lamp.>
Thanks for your contributions to the hobby!
Jeff
<Hope this helps, Rich...aka...Mr. Firemouth>

Re: 150W lighting - 11/26/07
Thanks for the reply. I've got a follow-up question. After investigating Sanjay's lighting site it appears that most of the 150w de bulbs draw 200w when run on the HQI ballast. Since the PAR values are much lower on eballasts for the 150w bulbs, it seems like I would get better efficiency by using a 175w system (they draw around 175w and most produce more PAR than the 150 watters which are drawing 200w). I guess the only downside is the somewhat limited choice in bulbs.
Your thoughts?
Thanks again.
<You have effectively answered your own question dead on! The only real reason not to use the 175w is bulb availability and diversity. For that reason the 250w lamps are the most popular in the Metal Halide arena. Higher PAR and more choices. Being that you have an interest in Acropora I would prefer to see you use the 250w if you plan to upgrade. These would keep the clams happy as well. Good luck with your choice-Rich...aka...Mr. Firemouth

UV Radiation And Metal Halides 8/28/07
I have a question regarding ultraviolet light and metal halide bulbs. I have two 150-watt, HQI fixtures. The fixtures are Coralife Aqualight Advanced, hang on the tank style. Anyway, I did an experiment to see if any ultraviolet light was escaping through the glass UV shield (a columnar shaped thick piece of glass that fits around the bulb). I used the plastic of a type of sun screen that turns blue upon exposure to UVA/UVB radiation (Blue Lizard is the brand). Anyway, the plastic immediately turned a deep blue, just as quickly as it does to exposure to noon day sun. I've read that glass filters most of the UV out, but my little experiment suggests otherwise. I tried it on another aquarium with power compacts, and the plastic barely turned a hint of blue when it was within an inch of the bulb. So, my question is, should I be concerned about the MH bulbs? Does the glass only filter the UVB and the UVA is what's turning the ultraviolet sensitive plastic so blue?
<Gary, without knowing what levels of irradiation triggers the test piece, It would be difficult for me to give an accurate answer. A better test would be to put the test plastic on the tank bottom and/or mid-level and see what happens. I'm guessing the plastic material is sensitive to residual amounts of radiation. The glass shield that came with your lamps should safely filter out dangerous levels of UV that could do harm to your animals.>
Thanks in advance.
<You're welcome. James (Salty Dog).
Gary

Metal Halide Lighting and Spectral Shift/Length of Efficacy – 05/14/07
Crew,
<<Mark>>
Thank you for all your efforts and advice; it really is appreciated by the majority of the users of the web site.
<<Thank you for this>>
I have a simple question that I can't find the answer for.
<<”Simple” eh? [grin]>>
I am sure it is probably in the FAQ's but I just can't find it.
<<okay>>
I am changing from power compacts to metal halides and I want to know about how often the bulbs need to be replaced to address spectral shift?
<<PAR as well as spectral shift need to be taken in to account.  There has always been/will be debate, but I read/hear more and more discussions, as well as my own anecdotal observations, that would indicate metal halide bulbs used for the hobby can be “effective” for as long as two years...maybe longer.  It appears higher Kelvin-rated bulbs (above 14000K) may shift more quickly, but are still “useful” well past the 12-month mark>>
With my PC's I am changing the bulbs around every 9 months, what is your advice on how often should I plan on changing the metal halides.
<<Consideration need be given to Kelvin ratings, lighting duration, bulb manufacture, etc...but as we learn more about the hobby/the animals we strive to keep and how the different environmental elements are intertwined (lighting, feeding, water flow, etc., etc.) and that no single element is more important than the other but all must be correctly applied to be in tune with the “balance” of the system...it is my opinion you should be able to get “at least” 16 months use from quality MH bulbs, and likely more than that>>
Thank you,
Mark
<<Happy to share.  EricR>>

Differences between MH bulbs  – 04/29/07
I'm in the middle of a local debate regarding MH bulb manufacturers.  There's a recurring rumor that all MH bulbs for reef aquaria are made in the same factory in China. 
<<Not so. RMF>>
 I don't believe it.  Second, regarding those no-name Chinese bulbs that are becoming so common, has anyone done a study to determine how they compare to the more expensive name brand bulbs, as far as spectrum shift, par and reliability?  
<Sanjay Joshi has done significant research on numerous bulb/ballast combinations.  As of April 8th, 2007 there are 916 spectral plots and performance data available for metal halide lamps and ballasts on his website.  You will likely find what you are looking for here:  http://www.reeflightinginfo.arvixe.com/
Hope this helps.>
Thanks
<Welcome!  Mich>

Re: Differences between MH bulbs  – 04/29/07
I looked there before emailing you.  Sanjay lists only name brand bulbs.  I'm referring to the no-name Chinese-made bulbs that you can get from eBay and sellers like Reefoptics.  Any data on them?
<Mmm, I'm sorry, I am not familiar with the bulbs to which you refer.  I would email Sanjay directly.  sjoshi@psu.edu  He may have the data you seek or be willing to do the testing.  Hopefully this will lead you to your answers.  
Good luck!  Mich>

Kelvin/Incandescence ratings...   4/21/07
Can you explain to me what the different colors and k's do?
What would they be best used for?
White 7100k is for?
blue 12000k is for?
pink 800k is for?
thank you
<The practical value of such ratings is covered on WWM: http://wetwebmedia.com/marine/setup/lighting/index.htm
In essence, there are "temperatures" that are of utility for engendering photosynthesis... starting at about 5,500K... "Warmer" lights for looks, depth... Bob Fenner>

When to replace double ended metal halide bulbs?   3/31/07
Hey guys your the best!   
<Thank you and hello.  Brandon here tonight.>
I was wondering when to replace doubled ended metal halide bulbs?  I read a lot about doing it when they start to flicker?  
<I would go with at least every twelve months.>
I know that the compact florescent bulbs are to be replaced at least once a year because they eventually stop putting out the same UV.   
<This time should be adjusted to every 6-8 months.>
Is this the same for  double ended metal halide bulbs?  
<Nope.>
I have had mine for about 1 year 3 months and seem to still work without flickering.   
<You are three months or more overdue for a change.>
What should I do?
<Replace your bulbs.>    
Thanks so much for your time!   
<You are welcome.  Brandon.>

Aftermarket HQI Bulbs? - 03/22/07
Hi guys,
<<Erinn>>
I am only asking this question because I could not find the answer anywhere else.
<<Ok>>
I currently have the Current USA Outer Orbit fixture 48" with two 150 watt 10000k HQI and two 130 watt dual actinic power compacts.  I have a mature 55 gallon reef tank with a wide assortment of mostly soft corals.  I don't like how the 10000k's produce such an overwhelming white-yellow appearance on the tank so I want to upgrade to 14000k or 20000k.
<<I see>>
I am worried the 20000k will produce too much blue so I am leaning towards the 14000k.
<Would be my choice as well>>
Do you guys like the Coralvue brand?
<<I don't have any personal experience with this brand, though it does seem to be becoming a popular favorite...likely due to its price.  The Coralvue bulb is worth trying I think, though my fave pick is those offered by Ushio>>
Second, I found a guy on EBAY selling aftermarket bulbs for about 18 dollars (really cheap).
<<Mmm...careful...>>
I don’t know if I should trust these bulbs?!
<<I wouldn't>>
He says they're new and closely resemble the Coralvue.  Have you ever heard of knock-off brand HQI bulbs?
<<I've heard of some cheap Chinese knockoffs, yes...and the subsequent "poor" quality/color rendition/service life...I've also heard about knockoff actinic bulbs that were simply white fluorescent tubes "painted" blue.  So, pay your money and take your chances...>>
Thanks in advance for your expert advice, Erinn.
<<Is a pleasure to share.  Eric Russell>>

Which Metal Halide Bulb? - 03/11/07
Hi All,
<<Howdy Robert>>
I'm getting ready to switch my 250-watt 5500K bulbs out for some new XM bulbs and I was wondering if you could give me some advice on which would be both better for my corals and at the same time be pleasing to the eye.  I'm looking at either the 15000K or the 20000K and the listings confuse me a little.  I want to get rid of my VHO setup I'm running with my MH.
<<I see.  You don't mention "what type/species" of corals these lights will be over...but even so, the 15000K should be fine/are the better choice in my opinion.  I've heard Sanjay Joshi remark that there is little difference between bulbs in the 14000K - 20000K range.  I've no wish to dispute his findings/opinions, but I do believe there is more useful light in the "yellow" spectrum in a 14/15000K bulb versus a 20000K bulb...and the "appearance" of the lower Kelvin temperatures is definitely more to my liking>>
Now I know people who are running the 15000K bulbs and they look great, but when I look at the different web sites they say actinic supplementation may be needed.
<<Mmm, not required for the benefit of the "corals" >>
But then people also tell me that the 20000K are going to be way too blue which I don't really like either.
<<Am in agreement>>
Can you give me your slant on this situation?
<<Happy to...go with the 15000K bulb.  Or better yet, choose a better/more reliable (in my opinion) bulb manufacturer...perhaps the Ushio 14000K (my first choice), or the Hamilton 14000K>>
Thanks,
Robert
<<Pleasure to share.  Eric Russell>>

Color me happy or color me healthy? 2/16/07 SW, lambda MH temp.    02/17/07
Thank all of you for doing a wonderful service to us by sharing your knowledge.
<Thank you. Labour of love, oh yes.>
Now, I have looked through think and thin and can't find the answer I need.
<Bet I can.>
I have a 110 gal reef tank. I have 2-175(10k)watt & 1-250(14k) watt halides with 2-96 watt PC's(03's).
<Good amount of light!>
It is getting to be that time for new bulbs in the 175's. I keep alot of SPS's.
<That would explain it...>
What I'm looking for is to help color up the corals. Does the Kelvin effect how the corals color
up? Will a 20k bulb intensify the colors more than a 10k?
<Mmm... yes. No. Well, not decisively. I think that as a rule, you will see more of the fluorescing colors when illuminated under high-UV light. As for production of pigmentation unrelated to food-production, it has not been "proven" one way or another exactly what influences the coloration of corals most directly: environment, diet & nutrition, lighting, perceived threats/or other stimuli. There is some speculation on whether lighting plays a big role in the pigmentation. It stands to reason, as pigments are in the visible spectrum of light, no? There is a neat back-and-forth with a bit by Eric Borneman on the topic, here: http://www.wetwebmedia.com/stonyfaq.htm . I think you will find, by and large, that most SPS-keepers have to decide to utilize light in the "usable" spectrum; i.e.., Yellows, greens, reds like the noon sun, or to utilize "aesthetically pleasing" spectra that contain more light shifted toward the 420nm scale. I think most of the pictures of attractive SPS systems are lit with 20K HID, or 14K with lots of 420nm.>
I have asked this question on a number of different forums and I think it stumped a lot of people.
<On that note, you will find enough to make your nose bleed here: http://wetwebmedia.com/marine/setup/lighting/index.htm . Be sure to spend the next week reading every link you can find on the subject here on WWM. There is so much on this topic here, you will likely find some conflicting info, but keep in mind that these are largely based on opinion. You want opinions. If you want fact, it's in the articles, but the actual application of these facts are open to interpretation and various levels of enjoyment and agreement by all.>
Thanks ahead of time for your help.
<You're welcome, Lee! Good luck!
-GrahamT>
Lee

Lighting/Metal Halide 1/30/07
Hey Bob,
<James with you today.>
Love your website.
<Thank you.>
It is coming that time again to replace my metal halide bulbs again. I have a 125 long reef tank that I have been running 14K bulbs with. I have soft, hard, SPS, and one L/T anemone, all is <are> doing well. My theory has always been, if it isn't broke, don't fix it. But with 3 years of 14K I'm feeling like a change. My question is, can I use 20K bulbs ILO <in lieu of> the 14K? I don't have room for supplement lighting and really don't like the look of mixing the metal halide bulbs. (I have 3-250W bulbs in my fixture) I have a LFS where I have seen them use 20K and 14 or 10K mixed on a 500 gallon reef and did not care for the look.
I have seen they have 15K bulbs available now but I am not sure if I will really notice a difference (Any input here would be appreciated also).
Would need a side by side comparison to see the difference.>
So tell me, can I use all 20K without depleting my light loving corals of their needs to thrive? Or should I stick with the 14K or just try the 15K?
<If it were me, and things are going as good as you say, I would leave well enough alone or go with the 15K.  Going with 20 lamps may lead to a spectrum adjustment period for the animals.  Your LTA may even move, and we do not want that with corals present.  Stick with the 14-15K, it's telling you something.>
Basically I am looking for a more blue look to the tank, I think it shows the colors of the fish better and brings out the colors of the corals as well. This is my goal without compromising coral needs. Please advise oh reef master!
<Going with 20K isn't really going to give you the difference in color appearance you seek.  You would have to go with supplemental actinic lighting for this, and since you have no room for this, enjoy the nice rippling effect the halides produce.>
Thanks in advance,
<You're welcome.  James (Salty Dog)>
Chris

Re: two different color bulbs <MH fixt.?>  1/31/07
I have another
<Where is the prev. corr.?>
question for you sorry its
<it's>
so soon but I have had my halides set up for quite a while and one of the bulbs was burning a bright white color the other was burning fine (400w14k) Its
<It's>
a long story about how I ordered the wrong mogul sockets for my ballast. But my local aquarium store owner rewired two sockets with the write
<right>
connections for me but like I said one is burning the wrong color is this the wiring or is it the bulb (Hamilton). And is this affecting the wattage at all Thank you.
<Can/could be... it is indeed dangerous to mis-match MH/HQI ballasts to improper wattage lamps... I would be checking these carefully... assuring they are suitable. Bob Fenner>

Re: Metal Halide question  - 1/18/07
Hello again Justin!
<Hello again, Jason!>
That is if you're still around.
<Mmm, all too often I'm afraid *grin*>
I have a 30 inch Current-USA SunPod MH with a single 150watt Lamp in it. For one I need to replace it because it's nearly a year old.
<Ok>
I was curious if I'd be able to replace it with a higher wattage lamp. They make the same size Pod that comes with a 250 watt lamp, however would I be able to put a 250watt lamp into my fixture even though it came with a 150? Just curious.
<Unfortunately, no, it's not that simple. With HID (High Intensity Discharge) lamps, bulb rating is based on the ballast that is equipped with the fixture. The ballast with your SunPod is likely rated specifically for a dual-ended 150 watt lamp. Sorry, bud! -JustinN>

Metal Halide Burn In Period??? 12/18/06
Hi, your web site has been a great help over the last couple of years.  But, know I think I finally have a question, that I cannot find on your site.
I recently upgraded from a 55 gallon reef to a 120 AGA.  With the upgrade, I also decided to switch over the metal halides, since I want to eventually get into acros.  I have 2x250watt MH with electronic ballast and also 2x96 powercompact actinic.  This whole system is new to me, I just received it last week.  To my disappointment, the unit only came with one 10k double ended HQI bulb.
<Whoa, whoa.  You say you have a 250 watt dual MH system, then you say it came with a HQI bulb.  Both of these systems are completely
different.  I'm guessing you have a HQI system.>
This bulb works in both units with each separate ballast, so I know the system is capable of working.  Since I only had one bulb, I thought I might as well upgrade to two Hamilton Tech 14K 250 watt.
After installing these bulbs, nothing has happened.  No light whatsoever.  I even placed the original 10k bulbs to make sure the unit was still working.
<And it does?>
Now the new bulbs have been in for about 30 hours without nothing.  I was told by one supplier that this was a normal initial burn in period and since the bulbs were different it might take 24-48 hours.  Is this true, I thought during the burn in period, the lights still came on.
<What mental institution is this supplier located at?  There is no such thing as a burn-in period.  As you say, the bulbs should light, period.
I'm guessing the lamps you purchased were defective.  Did this unit come as a complete kit, or is it a complete fixture?  Very unusual in that they would only send one lamp with a two lamp system.>
Please  help, I am completely lost with what to do next.
<Send me a link to this site if you bought them on-line.>
Thanks
<You're welcome.  James (Salty Dog)>
Greg

Re: Metal Halide Burn In Period??? 12/19/06
http://www.aquatraders.com/index.asp?PageAction=VIEWPROD&ProdID=307
Thanks for replying so fast.
<You're welcome.>
here <Here is> the link for the lights i <I> bought.  the <The> light system works with the bulb that they sent currently.  when i <When I> say they only sent on <one> bulb, they actually left on <one> out of the system - i <I> assume by mistake.  i <I> hope this helps answer the question regarding why this supposedly electronic ballast will not light up the hamilton <Hamilton> 14k.
<The ballast should light the Hamilton lamp.  I'd make sure there is no protective tape on the contact pins of the lamp.  If not, I'd be sending the
lamps back to the dealer.  In future queries, please cap words that begin a sentence and proper nouns, it saves me time from having to do it before
they are posted on the dailies.>
thanks <Thanks> again.
<You're welcome.  James (Salty Dog)>

5500K Bulbs 10/22/06
Hi All
<Greetings>
I’ve been working on a 157 gal reef tank now for almost three years, buying the best I could as I could afford it.
<Good way to go…saves the headache later>
It’s all about to come to life now but I need to know how to match up some bulbs for the best effect, both coral growth and looks. First I see a good deal of the people are using 10,000K metal halide bulbs, but the guy at my LFS said he used 5500K’s so that’s what I purchased and that’s what I’m going to use this first go around. I just purchased a 4 bulb Icecap 660 set up to go with my MH and would like to know what bulbs will work best with my 5500K’s.
Thanks
Robert
<Robert- I would recommend using super actinic VHO bulbs.  The 5500k’s will produce a reddish/yellow color, but if keeping SPS, your growth should be great.  Just remember that you should take your time in acclimating corals to the new lighting.  Cheers! – Dr. J>

HQI Installation 9-19-06
Hello,
<Greetings>
I'm going to be installing a new 150w bulb (14K Phoenix) in my SunPod as soon as it arrives, and I'm not 100% sure of the process of how to install it.  I have removed the old bulb, and know that the bulb is held in place by the two sockets that both push on the bulb from opposite sides. <Correct>  I assume that I need to pull apart the two sockets a little bit, then place the bulb in there and slowly let the two sockets press against the bulb? <You got it> All while keeping my skin oils off of the bulb.  Am I on the right track? <Dead on> Is there a "wrong" way to put it in, like upside down or backwards? <Luckily they make them so they only go in one way…the right way> I wouldn't think so, but I'd hate to find out the hard way.
Thank you very much, <Our pleasure. Cheers! – Dr. J>
Joe Schneider

Metal halide bulb brands   4/26/06
Hey.  I need to buy some new bulbs for my aquarium and am having some difficulties deciding on what type.  I have 2 175 watt bulbs over my 55
gallon right now.  I was wondering if you have ever heard of or know anything about the brand "Aragramax".  I was attracted to these because they
are only $35 a piece as opposed to $70 for Ushio and Hamilton, which i have also been considering.  In your opinion, how much emphasis should be placed on the brand?  Would you go with the cheaper or more expensive bulbs?  Ushio or Hamilton?  Any other brands you could recommend?  thank you in advance
<Hello Jon. John here this afternoon. My opinion is this: You could ask twenty people the same question, and get twenty different answers. You'll find that most people will actually recommend what they are currently using. With the exception of a couple of major outstanding brands (the two you mention not included), many bulbs come from similar sources. With regards to aesthetics, the colour rendering, even for bulbs with identical Kelvin ratings, can vary widely. If you can find any local reefers, or pictures on the Internet, then they may help you make your decision. As for quality, with the exception of a few German-brand bulbs, I have not found most cheaper-brand bulbs imported from Asia to be significantly inferior (indeed, I sell them myself). Best regards, John.>

Re: Reef Lighting    5/2/06
Salty Dog,
<Scott>
Can you please provide me with a website or distributor that I can obtain the 175W HQI bulbs at?  I am still having trouble locating anything besides 150, 250, or 400W bulbs.  Thanks.
<Can't provide you with this as there are no 175 HQI's.  Sorry for my mental error.  In your 24" deep tank, I would go with three MH175's, minimum.  That should give you enough lighting for keeping clams, SPS, etc.  This suggestion is based on a on-tank fixture only.  If hanging lights are desired, I'd step up to three 250's, preferably HQI's.  Three 250 HQI's would not be too much light in a on-tank fixture also.  James (Salty Dog)>

Re: a question left out of my earlier MH email ... lamp choice   5/9/06
Sorry, one more.
<Uh... of what? Where's the previous correspondence?>
The choices I have found for a replacement 250 watt MH bulb are more numerous than I anticipated.  Can you please recommend one of the following for my ritteri Anenome?  Those in bold are labeled as aquarium bulbs:
1) Ushio/BLV 10,000 K (cri not listed)
2) Ushio 20,000 K (cri not listed)
3) "Standard" 10,000 K (cheapest, but I don't care)
4) MegaChrome 14,500 K (cri not listed)
5) MegaChrome 12,500 K (cri not listed)
6) Hortilux Blue 6,500 K, 90 cri
7) Eye 6,500 K, 90 cri
The is in reflector, suspended 8 inches off the water.  My Ritteri is doing very well, and I would like to keep it that way.
Thanks again,
-Kevin
<I'd go with number 1... Good bulbs, about right temp. Bob Fenner>

Which 150w 10,000K MH Bulb? - 07/11/06
Hi,
<<Hello>>
I have a simple question (I hope) but as always I know you appreciate a little background.
<<Yes, thank you>>
I have an Outer Orbit light fixture with 150 watt MH HQI 10,000K and two actinic PC's.  My tank is a 58 Oceanic show set-up reef style with a DSB and fuge.  I mainly keep SPS and clams but have a few LPSs and plenty of softies.  My light fixture is about 3 to 4 inches off of the surface of the water with nothing but the glass lenses on the fixture between the water and the tank.  Everybody in my tank is and has been happy for the past year that I have had this light but now it is time (at least to my understanding) to change my bulbs.
<<Mmm, yes...likely overdue on the PCs (usually changed at 6-8 months)...might could get more use out of the metal halide (highly speculative), but changing at 12 months is a popular notion>>
I plan on buying the same PC's that came stock in the fixture but I am having trouble deciding what kind (brand) of MH to get.  I will still get a 150 watt and 10,000k bulb.  I hear XM's are nice but people tell me that they lose their effectiveness after about 6 months, is this true?
<<Can't say definitively, but I have friends who have had negative experiences with this brand...mostly early failure of the bulb to fire>>
Please help as I have been searching for an answer to this question for several weeks and nobody I have talked to as of yet have given me any suggestions.
<<For my money...I would get either the Ushio or Aqualine Buschke (AB) 10,000K bulb.  The AB will appear "slightly" more blue than the Ushio, but choosing either manufacturer will provide you with a quality bulb>>
Thanks much I am grateful for all the help,
Adam
<<Happy to assist, EricR>>

Matching MH Bulbs to Ballasts - 07/21/06
I bought 2 175W HQI DE 20k MH bulbs on eBay for $20 in a bulk box of mixed type MH bulbs.  
<<175W double-end (DE) bulbs?  Are you sure?  I didn't think there was such a bulb...nor does a quick Google search find one...curious>>
My questions:
1.)  Can I run them on the same ballast as the 175w SE bulbs or will I have to upgrade to different ballast.  One of my ballast is the Advance F-can (72C5581 N-P) ballast.
<<I believe this is 150W ballast, is it not?  It will not run the 175W bulbs...DE or otherwise>>
The other is DIY Advance ballast.
<<Mmm, this tells me nothing...>>  
2.)  Should I upgrade to one of the HQI ballast or just plug and play?
<<If that is a possibility, then yes.  My favorites are the IceCap electronic ballasts.  Great product/customer service/warranty...in my opinion of course>>
3.)  Will a 150w HQI <<bulb>> be able to run on these type of ballast also?
<<Are we talking about the F-can ballast again?  Maybe, though I think unlikely unless that model was specifically designed for such a bulb>>
Thanks,
Shaun Montgomery
<<Regards, Eric Russell>>

Re: Matching MH Bulbs to Ballasts II - 07/21/06
Yes there are a couple of 175 DE bulbs on the market.  Aquatrade sells them with their MH fixtures here: http://www.aquatraders.com/index.asp?PageAction=VIEWCATS
<http://www.aquatraders.com/index.asp?PageAction=VIEWCATS&Category=49>
&Category=49
http://www.aquatraders.com/index.asp?PageAction=VIEWCATS
<http://www.aquatraders.com/index.asp?PageAction=VIEWCATS&Category=24>
&Category=24
<http://www.aquatraders.com/index.asp?PageAction=VIEWCATS&Category=49>
<<Mmm, yes...have seen these (advertised) before now that you mention...>>
Also what is the bulb type of 175 DE and 150 DE bulbs.  (EX. 175 SE are M57)
<<Don't know/am aware the DE bulbs have a "type"...perhaps if you contact the manufacturer re...>>
Can I build a DIY house for the double ended bulbs and just buy the UV glass?
<<Sure>>
Or do I have to buy the full reflector.
<<Nope, you can find/buy the UV glass online.  Some brand names are Optivex, UVILEX 390, and OptiClear...likely others can be found with a Google search re "UV Filter Glass">>
Thanks,
Shaun Montgomery
<<Regards, EricR>>

HPS/Metal Halide Conversion Bulbs?   8/24/06
Howdy Folk,
<Hi Zach>
Love you books/website.
<Thank you.>
I have a 250 W HPS S50 ballast that I currently have a 4000K bulb in.  I want to get a higher Kelvin temperature for obvious reasons but the highest Kelvin conversion bulb I have been able to find online is an Ushio 250W 5200K 85 CRI Universal Metal Halide Conversion Lamp.
Will this work or do I need a higher K value?  If I need a higher Kelvin value where can I find the bulb?
<What exactly do you mean by a "conversion bulb"?  What are you converting?>
Thank you,
<You're welcome.  James (Salty Dog)>
Zach Alexander

Re: HPS/Metal Halide Conversion Bulbs?  - 08/26/06
I have a High Pressure Sodium Ballast with a Metal Halide "conversion bulb" in it that is only 4000 Kelvin.  I am not currently using this lighting system because I would like something around 6500K but the best "conversion bulb" I have been able to find is this one
http://www.businesslights.com/product_info.php?products_id=1413.  Any suggestion?  And would the 5200K be okay or would I have algae problems.  
<Ah, I see, not using a MH ballast.  The 5200 will be much better than the 4000 with very little yellow tint, if any.  Algae problems come more from nutrients in the water, the lighting just propels the process.
James (Salty Dog)>

Re: HQI recommendation 7/19/05
Ok, I read about it, and now I have more questions.  My tank is 48x15x15 (about 50 gal) is not too deep, so with 330 VHO watts I think is not mandatory the MH for the less demanding anemones... quadricolor?
<A good choice>
I just bought 3 lamps to change the old ones (1 white actinic, 1 blue actinic and 1 Aqua sun all from URI, 110w each one) Is this right?
<Your choice/s... actinics are more for show than go... more aesthetic than functional>
if the quadricolor is not a good choice under this scheme, what anemone you think will respond with this light?
Greetings.
Carlos Rafael Díaz Rivera
<Sigh... please read here: http://www.wetwebmedia.com/marine/inverts/cnidaria/anthozoa/anemonelightngfaqs.htm
and the linked files above. Read. Bob Fenner>

Halide bulb selection 8/18/05
Hey guys,  I have a 150 watt metal halide bulb (10000k) it looks too yellow for my tank. I am going to purchase a higher k  I would appreciate it if you would tell me the best bulb for my double ended fixture. I was looking for something that's not all blue but has a nice tint to add a bit of deeper water look.
List
13,000k Geissmann MegaChrome
14,500k Geissmann MegaChrome
20,000k AquaLine
20,000k Geissmann MegaChrome
any other bulbs in the blue coloration and are 150 watt you know of that are better please let me know.
Thanks for your time.  <Aaron, the 10K bulb shouldn't look yellow at all.  Wondering if the bulb is defective or you have an excessive nutrient problem making the water look yellow.  James (Salty Dog)>
- Aaron

Question About CRI Colour Temperature and UV Filtering  9/17/05
Hi Crew, <Hello Brad>
I looked in the posts to try to find the answer to this question. I found the question was asked but I did not understand the answer posted.
I am researching metal halide systems and found that bulbs in the 5000 to 5500K range have High 90+ CRI values. When looking at higher temperature bulbs (10000K) I notice that the CRI drops to around 65. These numbers are taken out of manufacturer catalogs for commercial bulbs. It makes sense to me that the CRI will drop the further you get away from the 5500K  mark. I just want to ask if my assumption is correct,<Yes> or if there are some special marine designed bulbs in the upper temperature range that have higher CRI values. <A color rendering index of 100 would be equivalent to high noon in the tropics, that is, the most natural color.  A lower CRI does not necessarily mean the light is no good for your corals as certain wavelengths filter out very quickly the deeper the light penetrates the water. These high temp bulbs at the proper wattage per gallon (4 to 8) provide enough intensity for the corals to live.  The higher temperature bulbs (10K+) are closer to the color you would actually see on the reef.  Hope this makes sense.  Just got back from the madhouse in Detroit and the mind is foggy.>
I also read in one of your articles that unshielded bulbs can put out dangerous UV A, B,& C rays and must be filtered. Is a piece of glass placed on the output end of the fixture adequate to filter these harmful rays, or are there special lenses you need to get for filtering purposes. If you need special lenses do you know of any sources?  <Glass works, but acrylic is better, no special lenses needed.>
Thank you for your help. <You're welcome, James (Salty Dog)>
Brad

Halogen vs. metal halide 11/6/05
Hi guys 
<Hello Archie>
I would like to know if plain halogen lamps will be as effective for corals and anemones as metal halides would be? 
<I don't know of any halogen lamps that would be an effective replacement for halides. James (Salty Dog)> 

Metal Halide Bulb Brands 10/30/05
Hello Mr. Fenner,
<Actually Adam J with you this morning.>
I was wondering if you had any information about the Iwasaki 50k de metal halide bulbs available.
<I have only seen this bulb in usage once and I do not have any personal experience with it though I have used other XM bulbs and they are a "Quality" brand as for the Kelvin rating...its aesthetically pleasing but most animals hosting zooxanthellae prefer bulbs with temps in the 6500K to 10000K range. You could use this bulb to supplement a lower temperature bulb to get the look you want.>
I know they have been talked about before but I thought by now there would be some better evidence about whether they are any good or not, when used over a reef tank.
<See above.>
thanks
Ben Hustwayte
<You are welcome, Adam J.> 

Reef Lighting and Kelvin Ratings 10/27/05
Hello and thank you in advance for your needed help!
<Hi Jon, and umm…your welcome in advance.>
I am currently thinking of expanding my horizons of aquarium size and have a lighting dilemma. The tank that I am getting is 180 gallons which is 72x24x24. On my current tank I am running one 10k 250w AB HQI with VHO actinic. My livestock is a mixed garden (including SPS and clams) to say the very least. 
<Ok, so a shallow water biotope.>
My questions are the following: would one more equal halide fixture be sufficient on a tank that size; or would three be better? 
<Three is the recommended number if you want to continue with the SPS and Clams. One bulb per 24” of tank length is a general recommendation.> 
Also I am considering moving from 10k to 20k (also in the AB line of products) in order to achieve a bluish white color. Would my mixed garden corals suffer from this regiment of lighting; or should I remain on the path that I am currently following? 
<Mmm, photosynthetic animals prefer lighting in the 6.5K to 10K spectrum so out of three of your bulbs I wouldn’t go all 20K. 14K at the most, but honestly 10K with VHO actinic supplementation is the best way to go in my opinion. Maybe you could mix bulbs, a 20K on the middle with 10K on the ends. Its your choice in the end, and you probably could get away with 20K but some animals may have to be left out and expect slower growth.> 
Do you have any further suggestions of how I can achieve the “look” for my aquarium that I am seeking?
<Just the above.>
Thank you very much for your time and expertise. It is greatly appreciated!
Respectfully,
Jon
<You are welcome, Adam J.> 

Lighting follow-up - 29/11/05
Could you please tell me the difference between a Aqualine Buschke, Super White Blueline, an Ushio, and a XM , all of which are 10000K MH?
<Your choice will come down to aesthetic preference. Ushio, XM and Aqualine are all very good brands. I have found AB bulbs (never tried 400 watters, mind you) to be excellent in terms of quality, but a touch on the yellow side for my tastes. Despite this, corals do seem to love the light, and the yellow can be balanced with actinic supplementation. Many people rave about the colour of the XM bulbs. 
I would urge you to look at reviews of these brands, pictures of people's tanks, and decide for yourself. In addition to reading through our lighting FAQs, it would also be worth checking out Sanjay Joshi's excellent site on lighting here: http://www.reeflightinginfo.arvixe.com/>
I want to buy the best one for my reef. I also have a 96watt Coralife. Is it a good idea to use this along with the 10,000K MH for aesthetic?
<Yes, an actinic would help balance out the slightly yellow caste to some 10,000K bulbs. However, whether the intensity would be enough to make any major dent on the output from a 400W halide is questionable. One thing is for certain: You have a great deal of light over a 50g tank.>
Thanks.
Ron/Jenn
<Best regards, John> 

Which Lighting Spectrum? - 01/17/06
Hi Guys,
<<Some sharp gals here as well.>>
Rob here from South Africa.
<<Howdy Rob...EricR from South Carolina here tonight.>>
I just have a quick question.
<<ok>>
I ordered a lighting system that includes, 3 MH 250w each and 8 T5's.  My question is...The supplier only has 6500K and 14000K bulbs to choose from.  Which would be the best if it is going to be for a tank containing clams, Ricordea, and some other light loving creatures.
<<As far as the critters are concerned, the 6500K will provide all they need as well as giving you the most PAR.  But most folks don't care for all that "natural" look and want a bit more "blue" to their "hue."  A good compromise might be to get the MH bulbs in 6500K and the T5s in 14000K.>>
Always appreciate your help.
Rob
<<Always welcome, EricR>>

Metal Halide Bulb Replacement Question   1/13/06
Hey guys.
<What’s up Jason?>
I'm a frequent reader of your FAQs and such.
<Cool.>
I have a question for you.
<Okay.>
I have a 40gal marine reef aquarium. I'm using a SunPod HQI lamp for the tank. Right now it has a 150 watt lamp in it at the moment. I wanted to know if it was possible to exchange this lamp with a 250 watt one.
<No the ballast with the product you bought is only rated for a 150 watt bulb, equipping it with a 250 watt bulb would at the least under-drive the bulb and at the worst cause a fire. Don’t do it.>
I'd like to optimize the most light I can.
<Though there will be some shadowing along the edges, a 150 watt HQI (generally speaking) is superb lighting for a 40 gallon tank.>
Thanks in advance.
<Welcome my friend.>
Jason
<Adam Jackson.>

Metal Halide Bulb Switch   1/22/06
Hello!, <Hello Lani> Hope all is well with the crew.  I have a quick question I haven't quite found the answer to.  I have a metal halide system with 2 250 bulbs and ballasts.  However, I decided not to do a SPS only tank, and was wondering if I could use 175 watt bulbs instead?
<Absolutely not.  You may start a fire.  James (Salty Dog)>

Double ended HQI bulbs   1/22/06
Hi guys!!!  I have said it many times but great site!!!!  Quick question....  Do you know what the white ends that hold double end bulbs into the pendant are made out of?  Is it ceramic??? <Yes> I got some shavings from the white pieces in the tank from the old bulb and could not get it all that fell in the tank.  Hope it is not bad for the fish and coral.
I guess it there is nothing I can do about it now just would help for to get my mind at ease.  I do not want to wake up and my fish and coral are dead...  OK maybe a little exaggerated. <No worries.  James (Salty Dog)>
Thanks

Re: HQI bulb    1/25/06
Thanks for the quick reply. I have one more question. I always seem to see a sump setup or a wet/dry filter with a light over it. Is this recommended?  Just in case, I am currently running a 65watt. 50/50 Coralife fixture about 8"-10" from my wet/dry setup. should I remove it or leave it. and what are the benefits of such a setup thanks a lot. <Any sump you see with a light usually has a compartment that can be used for a refugium.  In your case there is no  reason to keep a light over your sump.  James (Salty Dog)>

Question about Metal Halides  - 2/11/2006
Howdy crew,
Quickie on metal halides.  I have some SE Halide bulbs that were used for a few months max., but they have been sitting unused since for almost 2 years now.  Would these bulbs be "outdated" so to speak since they have been sitting so long,
<Would not worry here... the elements are not terribly reactive at low temperature in a sealed, evacuated tube. 2 years is not long in this case.>
or is the only important piece of info. the amount of usage time?
<Pretty much... within reason. Best regards, John>
Thanks for your time.   Paul

Lighting/Inverts/T5 lighting for 180 Reef   2/22/06
Hi James, <Hello Roger.>
After doing some additional research there seems to be varying opinions on T5 efficacy and I'd prefer to purchase a solution once given the expense.  Needless to say I also want what's best for the animals that will inhabit the tank.  Therefore I've decided to not step out of the box and go with tried and true MH.  I have a few related questions if you don't mind.  Any unsolicited advice is very welcome as well!
1.  I've read the rule of thumb is 1 fixture for every two linear feet of tank.  You'd mentioned two 250's but would 3 be more suitable? <Three would be more suitable if cost isn't a problem but if you went with two 250 watt HQI's placed on center 18" from each end (assuming a 72" long tank), you should have plenty of light.  Less light loving inverts can be placed on the ends.  Will only see some light loss on the last 6" of the tank.> 2.  10K bulbs seem to be the recommended frequency but there's different types.  One retailer alone sells Iwasaki, Ushio, Venture, Hamilton & BVL which vary by almost $40 in price.  Is there really a major difference between a $60 Iwasaki and a $95 BVL? <The more expensive bulbs usually produce a truer color temperature and a little more light output.> I'll be using an electronic ballast, probably an Icecap.  Not sure if that matters. <More efficient, bulbs last a little longer.>
3.  Strictly based on the bulb description the BVL sounds like it has more blue.  Does that negate the need for Actinics or are they still recommended?  Would a lower frequency blue be better either as an alternative or to augment the actinic? <In a mixed reef I would go with 10-14K lamps. Actinics aren't necessary with these color temperatures.> 4.  I'm going to be installing these in an 8" wood canopy.  What's the recommended ventilation scheme, number of fans, placement, vent holes
etc? <Two fans, opted for the highest CFM you can get that will fit in the sides of your hood.   I'd place one drawing air and one exhausting air.> I'd really like to avoid buying a chiller but I don't want the canopy to sound like the inside of a data center either if I can avoid it. <Might consider Ice Caps temperature controlled on demand fans.> Also, should I add an insulating material between the pendant and the wood (it would seem wise) and if so what do you recommend? <I wouldn't, may melt/soften.>
I apologize for dominating your time with all these questions but I'd like to preserve capital so I can afford to put something in the tank not just over it :) <I do recommend HQI, cleaner color temperature, bulbs last longer and takes up much less space in the hood.>
Thanks so much, <You're welcome.  James (Salty Dog)>
Roger

Lighting/Inverts  - 03/12/2006
Hi, my name is Danny Richards <and mine is James, how are you?> and I had a question about metal halide lighting for my 150 gal aquarium. The tank is 60"L x 24"W x 25"T and I am trying  to decide if I should use 3 x 250 watt MHs or 2 x 400 watt MHs. And also if they should/need to be DEs or Mogul. Other than being single ended or double ended,  what is the difference between HQI and Mogul?? I am wanting to keep SPS and  Clams with very few fish. Also what Kelvin rating should I use? I like the way  14K and 20K look, but I have had people tell me those color temps. are not good  for SPS and Clams. Thank you for your time, and keep up the good work! <Danny, to the best of my knowledge all double ended lamps are of the HQI variety.  The mogul socket is for metal halide and these lamps cannot be swapped using the same ballast.  I think HQI is the best way to go.  A little more intensity watt for watt, more compact in size, and generally produce truer color temperatures.  Bulbs generally last a little longer also.  I think two 250 watt HQI's should be enough for your tank, and I'd probably go with something in the 12-14K in temperature.
James (Salty Dog)>                                                                              
Danny R.

Higher "K" rating MH lighting
Hi crews,
A quick one here (hopefully).
I am running a 10000K 150W DE MH pendant on my 33 gallons (24"x18"'x18", 5" sand bed) and is hung 11" above water surface, water depth is thus about 12". Do I have enough to keep the most light demanding creature on sand bed?
I am thinking of changing to 20000K but afraid that it is not going to have enough PAR for the most demanding SPS or clam, as it seems that 20000K's PAR is about 1/3 of 10000K's of the same wattage. What do you think? What if I supplement with 2x55w day light PC?
And what about 14000K bulb? Which seems to be about seems that 20000K's PAR is about 1/2 of 10000K's of the same wattage. What if I supplement with 1x55w light PC?
Thank you very much for your time and effort.
Best regards,
Wid
>>>Greetings,
If the water depth is only 12", then you're doing pretty well with a 150W DE setup. However even then I wouldn't say you can keep ANYTHING - at least if you want the coral retain it's color. By this I mean some of the more demanding Acros out there. ALL clams will be fine. I find the 20k's MUCH nicer to look at, and they give much better color rendition. I just switched from 10k's (250W DE's) to 20k's a few months ago and couldn't be happier. Yes, you will lose a bit of intensity with the 20k's. Sure, you can supplement and increase the total PAR. I would stick with the single 150W DE, get a 20k bulb and be done with it.  There are plenty of nice corals you can keep, not to mention the clams. With a 33 gallon tank, your limited anyway as to how many corals you can keep.
I have no experience with the 14000K bulbs.
Cheers
Jim<<<

Higher "K" rating MH lighting - Part 2
Hi Jim,
Thanks for your swift response as always!
Went to LFS just now and looked at Iwasaki 20000K 150W DE, it is so white, only with a slightest hint of blue! And the LFS owner said that BLV will be just a tad bluer. I guess it all depends on ballast. If a 20000K bulb appears whiter, does it mean that it will have relatively more PAR than its bluer appearance counter part?
I just got a good deal from someone selling his 70W DE MH, I am planning to run a bluer 20000K 150W bulb for 10 hours a day and run the 70W on an industrial bulb (5000K-8000K depending on the bulb I am getting) to supplement the red and green range for 5 hours a day to simulate noon sun.
How does this sound to you?
Thanks again.
Wid
>>>Hey Wid,
All I can say is try it and see how you like the effect. The organisms don't require that you attempt to simulate 'noon' with a different color temp however. If it were me, I'd use the extra fixture to increase the total PAR on the tank for the entire duration of the light cycle.
Cheers
Jim<<<

Shrimp breeding and halide lights
Greetings Crew!
<< Blundell here today. >>
I just can't say this enough, but thanks for putting up such a great site!  I love reading the daily FAQ's and surfing through the archives.
Got two questions for you today.
1.  I have a 55-gal reef system (corals, fish, inverts, etc.) and I have one red skunk cleaner shrimp.  Today I noticed that he is actually a she as her belly is full of what I can only assume to be eggs!!!!  Now, I lined up the suspects in the tank and the only ones I can come close to thinking of are my pair of Fire Shrimp (one of which had eggs last week).  Is it possible for a fire shrimp and skunk cleaner to mate?  << I would have said no, but maybe you are proving me wrong. >> Or will shrimp produce eggs in absence of a mate and just hope they get "lucky"? << I wouldn't be surprised to see this happen.  Especially being hermaphrodites (well some shrimp I should say). >> The only other suspect would be my Coral Beauty, but I think his love affair with my cleaner is just related to the cleanings!
<< Agreed, at this point I'd be suspect, but potential cross breeding may actually be taking place. >>
2.  This is relating to metal halide bulbs.  I am totally familiar with wattage and degrees Kelvin (planning to construct a custom oak suspended canopy with 2x250W of MH).  I have a friend who works in an industrial supply company and they have hundreds of different MH bulbs in stock.  The problem is that the bulbs are rated in Lumens and color temp.  Is color temp the same as degrees K? << Yes, that basically means what colors of light are being given off.  In other words how much of the light is red, how much of it is blue and so forth. >> What are Lumens? << Lumens is how much total light is given off.  For instance you can have a very blue bulb that gives off only blue light.  But that light may be very dim like a moon light (low lumens) or it may be very bright like a search light (high lumens).  >> Is there a way
to compare these bulbs with those used in the aquarium  industry or am I comparing apples and oranges?
<< Well with a PAR meter you can really compare bulbs well.  But for the average hobbyist I think that comparing visual colors to you, and also Kelvin ratings is good enough. >>
Thanks again and have a happy Halloween!
-Ray
<<  Blundell  >>

What Kelvin rating to use
I have a 200 gal tank, 72" long.  For my light fixtures I have a Coral Life MH Fixture that Holds 2 175w MH and 2 48" Fluorescents, then I also have 2 additional MH fixtures that will hold 175w MH.  So in total I have the Ability to have 4 MH and 2 48" Fluorescents.  In this tank I am wanting to have probably Mushrooms, Polyps, Leathers, and things like this.
I am going to have some were around 200-300 lbs live rock.
Is my lighting sufficient or too much, and what kind of MH bulbs should I put in my fixtures, 10,000 k, 50/50, ???. << All sounds good.  I'd run 10k or maybe 14k halides.  I'd run some URI actinic for your fluorescents. >>
Thanks much for all the answers you can give.
John M.
<<  Blundell  >>

He Wants The Blues (20000k Blues, That Is!)
Hello Crew,
<Hi there! Scott F. here tonight>
I have read quite a bit about this question on your site, which has lots of great information,  but I am still unsure about this.  I have a 110g (24"deep) tank with 2x250w 10,000k HQIs which are 2+ years old.  I have BTA's and SPSs.  I REALLY like the look of the 20,000k bulbs and thinking of switching.  I read on your site that 10,000k is preferred for the BTA's.  Does this mean that the BTA's would really have a problem??
<Well, I don't think that they'd have a "problem", but I think that your anemone's would grow faster and generally do better under a more full-spectrum light...I am a huge fan of 20k's, myself, but the majority of 'em just don't carry the same "punch" as 10k's. However, I simply love them! They are still excellent bulbs, and will do a nice job with many corals and inverts, rendering excellent colors, albeit with slightly slower growth. Just understand their limitations and change them out regularly>
Like I said I love the blue look.  I have heard the SPSs would be OK.  If it is cool to switch do you have a preferred brand (XM MegaChrome, etc.) and what would you recommend for acclimation of the new 20k's. Thanks, Rich
<Well, my personal favorite brands of 20ks are Aqualine Buschke, Geissmann Megachrome, and Helios. Icecap is releasing a 20k bulb soon which seems really promising. Acclimation to these bulbs would be best conducted slowly, perhaps using the window screen technique, whereby you cover the area under the lights with a few layers of window screen, and gradually remove them as your animals acclimate. Good luck! Regards, Scott F.>

Re: lighting advice
Hi crew- <Hello, MikeB here.> This makes 2 questions in one night, and I apologize.<Not a problem, that is what we are here for.>  I have  a 90 gal, currently with 356 watts of mixed day/actinic PC's.  I'm upgrading to MH. I plan on keeping several SPS (Acropora), a few LPS, a Xenia, an anemone (bubble), generally mixed reef.  I am torn between the following lights (both include carrying over my 96w PC with 6700/10k bulb):  2x400w  CoralVue mogul 10K and 2x250w HQI Aqualine Buschke 13K.  This is a sizable  investment, and I want to make sure I make the best choice.  As always, your advice and information is invaluable, and I cant thank you enough.
James
<James, both lighting systems are great fixtures to add to your reef tank.  Either choice you make you can't go wrong.  I suggest you go with the 250 W HQI metal halides because you indicated that you want a mixed reef.  If you went with the 400's you would be supplying a little to much light for the LPS.  If you wanted a SPS tank only then the 400 watt fixture would be the way to go.  I would suggest that the 250 watt bulbs you try and get in 10,000 K output, 13,000 K is a little on the blue side.  Remember your tank is 4 inches deeper than a 75 gallon tank so the lighting will be softer at the bottom.  Good Luck!!! MikeB>

U.V.. risk using Sylvania Metalarc bulbs
Hello there, I have a few questions to make about lighting.
First some background data: I live in México and here is hard to find (not to mention the high prices) bulbs for the reef tanks.
I have purchased some XM bulbs from Marine Depot but last time had some trouble with the toll (they charged me 60% of the total value on taxes... OUCH!).
<Dang governments!>
Now I'm trying to use the materials I can find in the city. And since we are setting up a couple of tanks, the costs (as always ;-) matters.
<Same everywhere>
Now the question: I bought an Sylvania Metalarc halide 175W bulb (6500 K) in the past days, but I am concerned about the physical risk for using them.
In the box says: "This lamp can cause serious skin burn and eye inflammation from short wave ultra-violet radiation if outer envelope is broken or punctured".
I know it may sound silly, but I don't know what they mean with outer envelope... is it the glass? (I don't imagine a bulb with the glass broken working... hehehe).
<Likely you are correct here... modern non-fluorescent U.V. lamps have a coating applied to their outer surface or an outer envelope of filtering glass (as opposed to older styles that aquarists used UV filters that were additions to, components of the fixtures themselves)>
I have not found information about this in the Sylvania web page, so any help would be very appreciated.
Finally, do you think this kind of bulbs might be useful for coral propagation? may be used for some particular species?
Thank you very much for your time and advice.
Best regards: Carlos M. Storch
<Should be as long as the energy produced is of PAR (Photosynthetically Active Radiation) quality. You should look about on the Net, query the various specialty BBs (ReefCentral, Reefs.org) for input here. Bob Fenner>

Sylvania Halide lights?
Hello again, can you make a little correction in my FAQ, please?.
I wrote "question" twice, so please put a couple of "q" instead c... << No problem, I got it. >>
A little Spanish confusion... sorry!
Thanks a lot and best regards.
Carlos M. Storch
Hello there, I have a few questions to make about lighting.
First some background data: I live in México and here is hard to find (not to mention the high prices) bulbs for the reef tanks.
I have purchased some XM bulbs from Marine Depot but last time had some trouble with the toll (they charged me 60% of the total value on taxes... OUCH!). << Wow, that is high. >>
Now I'm trying to use the materials I can find in the city. And since we are setting up a couple of tanks, the costs (as always ;-) matters.
Now the question: I bought an Sylvania Metalarc halide 175W bulb (6500 K) in the past days, but I am concerned about the physical risk for using them. << They are fine to use, and will grow corals quickly.  However, they don't make the corals colorful. >>
In the box says: "This lamp can cause serious skin burn and eye inflammation from short wave ultra-violet radiation if outer envelope is broken or punctured". << Yes, I wouldn't worry about UV radiation with that bulb. >>
I know it may sound silly, but I don't know what they mean with outer envelope... is it the glass? (I don't imagine a bulb with the glass broken working... hehehe). << Yes, they mean if you break the outer glass layer. >>
I have not found information about this in the Sylvania web page, so any help would be very appreciated.
Finally, do you think this kind of bulbs might be useful for coral propagation? may be used for some particular species?
Thank you very much for your time and advice. << If you do use this, you will want to add a lot of blue actinic light to offset how yellow these lights are. >>
Best regards: Carlos M. Storch
<<  Blundell  >>

50000 or 20000 Kelvin bulbs
Hi!
When you search the Internet you can find a lot of information about the 50 000K metal halide bulb made by Iwasaki. Iwasaki has also got a new 20 000K bulb with higher lumen output. Do you experts have any opinion of the performance (success/failure) and the looks of this bulb? << I wouldn't buy a 50000 K bulb.  Do you mean a 5000 K bulb?  Either way a 20000 K bulb is plenty blue, but may not appear bright enough to you. >> How does it stand out compared with the 50 000K (the 50 000 seems to be considered "the best one" by many people)? << I think a 50000 K is way out there.  I wouldn't buy one.  I'd stick with a combination of 20000 K and 10000 K bulbs. >> I plan to have soft corals, mushrooms and buttons in
my aquarium (150W/45 gallons). << In that case, I'd stick with 20000 K bulbs. >>
Thank you.
Anders
<<  Blundell  >>

Lighting
Hi again...ask you something...about metal halides.
Are the ones used for signboards by the free way the same as the one used for aquariums...thanks...
>>>No<<<

Lighting Follow-Up
Ok, just suppose that I'm going to switch to MH, what would be your recommendation according to my tank length 4 feet and depth 1'3" in number of lamps, watts for lamp and °k ? <°k truly depends on the type of coral that you'd like to keep- Deeper blues are typically used for deeper water corals, and more whites are for shallow and lagoon corals.  I'd recommend a combination of the both if you'd like to have keep all types of corals.  2 lamps should cover the tank nicely, and between 5-9 watts per gallon is a nice wattage.  Good luck! Ryan>

Metal Halide retro question
Hello,
First I would like to thank you for you wonderful web site, great job!
My question is I have found the following 175W metal halide retro kit and wanted your opinion overall if I should consider or pass. Everything is brand new from petmeister.com.
The included bulbs are Catalina 175 Watt 10000K mogul based and the ballast is a Fulham Workhorse. They claim the ballast is compatible with any 175W mogul base bulb. I am not familiar with these brands. They are asking $229 for the retro kit which includes 2-175W bulbs, magnetic ballast for 2X bulbs, socket, reflector, mounting hardware & wires. I would replace the reflectors with spider reflectors for better light reflection as I am sure the basic ones included are not sufficient. Is this retro kit worth anything or should I spend more $ and go with more common brands such as Icecap, PFO etc for quality reasons? Any input would be helpful.
Thank you for your time.
Miles
<If it were me, my system, I'd return this gear and go with well-known brands. The Fulham brand is the real thing, but the lamps are engineered for outdoor landscape use... Bob Fenner>

Metal halides over the center tank brace
All:
< Blundell here tonight. >
   Thank you for your valuable advice.  I am in the process of upgrading the lighting on my 125 gal. 72X18X22.  I will be going with MH mogul based in 20K.  I will be purchasing a new canopy in either 10" or 12" depending on your advise.  I wish to keep LPS, soft and limited SPS.  I will keep the SPS confined to the upper 1/3.  I know these are broad categories, but I will place specimens as needed.  My question is should I go with 3 X 175 watts in a 10" canopy or 3 X 250 watts in a 12" canopy? < With those options, I'd chose the later.  The more watts the better in this case. > I have never kept SPS but it is my understanding that 20K bulbs don't put out the same PAR per watt as say 6500 or 10K's.  < Very true.  20k have better color for the corals, but grow slower and don't look very bright.  I use 20k now, but will probably switch to 14k or 10k next time. > Also, there is a 12" 1/2" thick center brace that one of the three lights will be directly over.  Is 10" or 12" of clearance in the respective wattages safe?  < It is safe, but the shadow of the brace really cuts down on how well that bulb will work.  You may want to have that brace replaced with acrylic, or have your lights staggered so that the middle bulb isn't right over the brace. > The canopy will be well ventilated (fans. etc.)  Thank You!
Ben
<  Blundell  >

Kelvin Temp  - 1/13/05
I have read your lighting FAQs and haven't seen my particular question.
<Then you missed it!  It's on lighting FAQ page 3, answer #14, paragraph 2, line 26, letter 47.  Just kidding>
I have a 225g reef that is 30" deep.  I have two 400w HQI Pendants with e-ballasts about 9" above the water.  Tank is at 80-81 stable (Night/day).
My question has to do with the temperature of the bulbs.  I don't have any other lighting and was wondering if I don't have adequate red  green spectrum?  There is plenty of intensity.... to the point where mushrooms, softies, etc need to be place in the centre of the tank on or near the bottom (two coral head reef setup) for them to open fully.  So my question is:  Provided you have intense 20k lighting... is it still necessary to have lighting in the 6500, 10k 14k area?
<As I am not aware of the species you are attempting to keep, I will provide as general answer as I can...at least for the species commonly kept in this hobby.    Most photosynthetic organisms from tropical reefs prefer 'warmer' Kelvin temperatures (5500k-6500k range) as they evolved to utilize sunlight, which is 5500k.  However, they are for the most part very adaptable, and should do fine with 20k lighting.  They will not grow as fast as they would under a warmer bulb, though>
Thank you for your help..... and what a great source of info your site is.  It is my primary source when
looking at new specimens or problems.  Thank you.
<You're very welcome - we try!>
Scott McAdam
<M. Maddox>

MH Lighting Question
<Hello Brandon>I've got a question on MH lighting. I've currently got a 3x250W system running with 2x96W actinic PCs. The MH bulbs are 10K XMs. I'm thinking about switching the system to 3x400W so that I can switch to the 20K bulbs. The PAR values seem to be horrible on the 250W bulbs. Is it worth the extra expense to go to 400W bulbs? I'm not sure how much the PAR would increase going from 250W to 400W on a 20K bulb. It just seems like the most popular reefers, like Tyree for example, are using 20K bulbs to get extreme colors on their acros. Any thoughts on the 20K colors, and the extra heat it would bring? It's a 125G tank, and I'm wondering if 3x400W would be overkill or cause much more heat? <Going to three 400's would definitely increase the heat level.  If these are pendants you could probably get away with it.  If they are hood mounted you'd probably have to go with a chiller.  I don't think the extra money for everything is going to be cost efficient.  Drs Foster & Smith sell the German MH bulbs in your wattage and in the 20K you desire. James (Salty Dog)>

Need a glass shield for halides?
Hi, and thanks for reading this....My question is regarding a 250 watt AB 10 K Mogul Bulb or any screw type metal halide bulbs...Do they need to be shielded because of UV rays or is the bulb case already producing the shielding effect ? < They do not need to be shielded. With the double ended bulbs it is a good idea, but for mogul base you are okay. > The reason I am asking is I wanted to maximize the amount of penetrable light into the tank...120 gal Standard Tank 19 inch water column after sand bed....Bulbs 9" from water surface... < Yes, you do cut down on light when you add the shield. Therefore I try not to have a thick shield. I like using 1/8" glass. It isn't very thick but it shields. Plus, I would rather clean the salt creep from my glass, than from the bulbs themselves. So a glass shield also helps with maintenance. >
< Blundell > 

Metal Halide/SPS Corals
After doing a search of your site I do have a question about halides for SPS corals. I have a dual 175 watt metal halide hood that is over a 46 gallon bowfront tank. Presently it has two Sunburst 12K lamps. I have heard quite a bit of mixed opinions on these lamps and would appreciate your opinion. I realize that these lamps have a lower PAR due to their color temperature, but are they satisfactory for the color maintenance of various SPS?  I would also like your opinion on using higher Kelvin lamps for color maintenance, i.e. will 10K lamps supplemented with VHO actinics provide the proper mix or are 20K preferred? 
<A lot of people are just using the 20K's now. Haven't heard anything negative. I personally prefer very little actinic in a lighting system. Here is a link I'll post. Adam Blundell wrote this article concerning coral fluorescence for Advanced Aquarists On-Line Magazine. Think you will enjoy it.> http://www.advancedaquarist.com/issues/feb2005/toc.htm.>
Thanks you for the help and I look forward to your response. 
<You're welcome. James (Salty Dog)>

Reef set-up/planning questions 4/14/-5
Hi Anthony,
<Cheers>
Thanks a lot for the last reply. You gave me the impression I somehow was on the right track. Reassuring. I have a few more questions, I'll try to be as short as possible...
-I've read somewhere on the WWM that MH bulbs should be changed each 2-5 years. That surprised me as I thought they needed to be changed each 12 months. Correct answer is once a year, right (and each 18 months for PC)?
<Not exactly... it depends on the bulb. Some need changed after just a year of use, while many last longer. Some of the best ones retain over 90% of their efficiency for the full life of the bulb (over 4 years in some cases. I had one go almost 5 years)>
-When buying a new MH bulb, there is a warning saying the bulb burns much brighter during the first 100 hours.
<Correct>
Does one have to let it burn 100 hours before use on the aquarium?
<Nope... not needed. But do try to use a sheet or two of fiberglass fly screen (window fabric ) to diffuse light during the break in period>
It means I'd have to turn hood upside down and illuminate the ceiling each night during a week, switching old and new bulb each evening/morning... Would be an annoying procedure.
-If I go with daily water changes, would 1 or 2% per day be sufficient?
<Larger weekly water changes would better help reduce nitrates, etc>
-Can I use Selcon in FW as well?
<Yes! Lipids/HUFAs are good for all>
-How can we know that a certain fish we are buying (from a frequently captive bred species) is really tank bred and not imported?
<There are no guarantees... but you must trust your LFS and your own good sense and intuition along with consumer research in advance>
I trust my LFS, but I don't know the persons they're buying from...
-If I use a Wave2K in my tank, can I place a central LR mound right on it (with clear space in front of vents of course) or do I still have to respect the 3" away minimum...?
<I'm really not sure. Do ask of the mfg directly>
-In what part of the sump should the evaporation make-up FW (from Osmolator) go ? In the first part with skimmer or in the last one close to the return pump?
<The last stage>
-Even though they are beneficial, I'm still not sure I want to see worms (bristle, spaghetti...) crawling around in my tank. Can I do as well without them with my DSB methodology (4" in display and in fuge)...
<Yes>
...if I rely on Nassarius, micro brittle/serpent stars, amphipods to do the trick (stirring/aerating)?
<Yeppers>
-I got interested in sponges after going through the Porifera chapter of "Reef Invertebrates". With the mix of corals we already discussed in my last mail (Euphyllia, xenia, and Montipora digitata), could I still add a pretty blue/purple Haliclona sponge?
<Yes... and be sure to give it high light and high water flow>
And also one cryptic species to make use of the shady zones of my tank (36" hood on a 48" tank = dim light on top sides of tank...)? Here if you could recommend one or some species (I like tubular species or with holes able to provide shelter to other animals) that would fit with my mix (not too noxious) and places where to find them. They don't seem to be readily available...
<Have you read the writings of Steve Tyree on the subject of cryptic refugia? Google until it hurts :)>
-Should I forget about keeping a crocea clam and a Lysmata amboinensis in the same tank?
<It is risky in the long term>
And what about a single specimen of "micro-hermit"? Very likely to pick on the clam I guess...
<I do not recommend hermits at all... they are too indiscriminate as feeders/predators>
-About phytoplankton reactors. I have seen heavy set-ups with reactors on the net. I think I don't want to get too involved with these. Would it still be worth it to simply use a single 2l pop bottle dripping in the fuge (as seen in Reef Invertebrates, p.54) without adding culture media. Would only use a strain to start the culture with new seawater (made from RO-DI) and no additives and adding new seawater as need is to compensate for the drip. Would it still be useful?
<Yes... it certainly can be :)>
BTW is there not phytoplankton in the system anyway, especially when using a lighted fuge with macro-algae?
<Yes... but there just is not enough produced naturally>>
-Back to the subject of getting an ocellaris to host a coral in my tank. I tough I took a step in the right direction by forgetting about the BTA and use a coral substitute.
<Excellent! thank you>
Seems I'm dead wrong again with Euphyllia. With the set-up I'm planning, I wonder if it's even worth trying to have an ocellaris at all. Let's say I have 2 or 3 Euphyllia and an awful lot of xenia (hopefully:). I guess it's maybe possible that the ocellaris would favor xenia and only host the Euphyllia from time to time.
<It is possible>
Is it something possible to have the corals in a set-up "share the burden" of a clownfish thus being able to get along with it?
<Rather than stress the corals... my advice is to forget about the mix in a garden reef tank, and set up a dedicated anemone tank, my friend>
Ok, Thanks again!!! Dominique
<Kindly, Anthony> 

Halide Lighting (Mixing Ballasts And Bulbs?) - 05/27/05
Thanks for the info.
<Welcome>
So I talked to the previous owner and he said they used to have two 400 watt bulbs but by accident bought the 175 and kept it and they used the same ballast as the 400, they didn’t change it at all.
<Hmm...I have heard/read about ballasts that claim to "adjust" to the wattage of the bulb, usually sold by greenhouse/hydroponics suppliers and geared toward very high wattage bulbs (400w/600w/1000w). I suppose it's possible you have one of these?>
Do I still need to change the ballast?
<You need to determine for sure which wattage(s) the ballasts are designed for and use a bulb of the correct wattage. If the ballasts are not clearly marked, contact the manufacturer. If you are running a 175w bulb on a 400w ballast it's my opinion you are risking catastrophic failure (explosion) of the bulb.>
One more thing, what is the difference between 10k, 14k and 20k?
<The "K" refers to the "Kelvin temperature" of the bulb which correlates to color rendition. The higher the Kelvin, the "bluer" the light appears. I recommend 10K bulbs due to their crisp white appearance, which to my eye, provides a more natural appearance than the more blue appearing 14K or 20K bulbs. BTB, even a 6.5K bulb contains more than enough "blue" for the animals we keep, thus choosing a Kelvin temperature generally becomes a matter of what is pleasing to us humans <G>.>
Thanks
<Welcome, Eric R.>

Lighting Decisions (Pt. 2)
Would I need to supplement an HQI system with actinics or would 2 150 watt HQI without actinics be sufficient?
<You would only need to supplement the halides with actinic if the bulb's aesthetics do not please you. For example, a lot of people feel that the popular 10,000k halides are too "yellow" for their taste, so they supplement them with actinic. There is no tremendous advantage in doing so other than aesthetics, however, IMO. Many hobbyists like to use actinics to simulate a "dawn" or "dusk" phase before/after their halides go on or off. Again, purely a judgment call on your part.>
Also on hellolights.com, it says that a UV glass shield is necessary to protect the life within the tank.  I have a glass canopy right now, is that enough?  Thanks again!
-Ron
<The fine folks at hellolights.com (a great company to do business with, BTW) are correct. Double-ended (HQI) bulbs do not have a "shield" like mogul-base halide bulbs do. Pretty much every double-ended pendant that is available in the hobby has the tempered glass shield built in, however, so if you intend to use these bulbs, you'll generally be using them in a hanging pendant that includes the glass, such as those made by Aquamedic, PFO, or Sunlight Supply. Do check them out! Good luck! Regards, Scott F.>

MH bulb replacement
Hello and thanks again for all you do.  Your website has been so helpful.  I bought a used MH retrofit on eBay about 8 months ago.  It was used for 6 months prior according to the seller.  I'm looking to replace my bulbs but don't know what type of ballast I have.  It is 2 x 175w.  Attempts to contact the seller have been unsuccessful.  I have been very happy with the light so far.  So how I determine what type of ballast I have so I can replace the bulbs?
My tank is only 55 gallon long.  I built a canopy which is suspended from my ceiling.  One bulbs is 20k bulb, one is 13k.  Also I have 4x 55w PC fixture in place (2 10k, 2 03 actinic)  I installed 3 cooling fans as well in the canopy to reduce the heat you can imagine is generated and temp is always below 80.  Inhabitants are various LPS, SPS, soft corals, anemone, mushrooms etc.  I would also like to keep some tridacnids in the future. In your opinion what would be a better combo....2 x 175 MH 10ks with 4 x 55 PC all actinic; or 2 x 175 MH 20ks with 2 55w PC 10ks and 2 55w actinics?  I know a lot is just personal preference and I do like a "bluer tank", just wanted a professional opinion. <Corey, if you like the bluer tank, then I would go with your last scenario.  James (Salty Dog)>
Thanks,
Corey

MH light bulb
Hi everybody. <Hello Nick.> I bought a 400w metal halide hanging pendant light on eBay for $58.00 with shipping on eBay if others need cheap MH lights.  These lights were hanging in peoples warehouses and they sell them  cheap!  So my question is , what kind of bulb do I get for it? I know I need the mogul base and I know I need between 10-20k of color.  But I have found bulbs in the shape of a pear, and bulbs that are long and skinny.  I have a 60 gallon corner tank and it is 24 inches tall so I know the pendant bulb is ok for this application.  So do I need the skinny bulbs or the pear shaped ones?
Thanks for the help and keep up the good work! <Nick, in the future please cap all your "i's".  It saves us work as we have to edit these queries for posting.  I would go with the pear shaped light.  The skinny ones are designed for horizontal use.  A 12 to 20K would be good.  If you like more blue, go the higher K route.  James (Salty Dog)>
nick

Sunburst Metal Halides 2/2/04 
I recently saw halide bulbs called Sunburst made by Aquatic Lighting Systems that are 12000K. Do you folks have any experiences with these 175 Watt bulbs? Being 12K I'm sure they would have a fair amount of blue in their spectrum and could probably be used without supplemental actinics, would this be correct? Thank you for the advice and for the help you folks give so freely. Matt 
<Hi Matt. I have seen these lamps, and would consider them to be similar to Radium 20,000K in appearance and intensity. IMO, they are quite blue (too blue for my taste, even without actinics, but this is very subjective), and for this you sacrifice some intensity. Kelvin rating is based on a complex calculation derived from the spectrum of the lamp and is often simply made up by the manufacturer, so it is not a reliable indicator of what the appearance will be. Best Regards. Adam>

Metal Halide lighting
Hi Bob,  
<Hi Larry.>
I'm up grading my 30 gal reef tank to a 55 gallon.  I currently have hard and soft corals with a maxima clam.  I am trying to decide on whether to use a 260 watt power compact light fixture or a hood with 2 -175 watt 6500K metal halides and 2 actinic 20 watt fluorescent bulbs. My question is how often do the MH's have to be replaced and are they more cost effective in the long run.
<Halides, (with the exception of 20,000k bulbs which are overdriven) on average, need to be replaced every 11-12 months. In the long run, halides are cheaper than fluorescent lighting. Watt for watt, they cost the same to run than fluorescent lighting. Watt for watt, halides emit the same amount of heat as fluorescent lighting does. As an example, 400wts of halides would have the same heat as 400wts of powercompacts would.
<<Graham... not correct. The measure of wattage is consumption of electricity... the heat generated is far different. RMF>>
  If you didn't already know, Metal halides release all of their energy in one small area which is why halides often seem hotter than fluorescent lighting. In the long run, halides can often save you money.>
I like the shimmering effect of the MH's but the initial cost is twice of the power compacts which will have 4- 65 watt bulbs, 2 -10,000k and 2 actinic.  Also, if I go with the MH is there any benefit with going with the 10,000K bulbs vs. the 6500K  aside from the whiter appearance.  
<The 6,500k bulb will have slightly more intensity, although overall, it won't make an extreme difference.>
I feel the mixture of the 6500K bulbs with the actinic blue would give a nice appearance to the tank.  I appreciate your input and your web site which has been very helpful in the past.  Thanks, Larry.
<I would actually recommend you buy 2x 250wt halides than 2x 175wt halides. The 250wt bulbs will give you much more intensity and will allow you to keep many more inhabitants, especially if they're going to be placed at the bottom of the aquarium. The cost should be about the same as the 175wt halides (of course, depending where you looked). However, Either choice would be good. Take Care, Graham.>

- The Holy Grail? 175 Watt, Double-ended Metal Halide -
Greetings!, having read and read, I am amazed at the amount of information you dose out on a daily basis. Having been on the reading end for so long,  I figured its time for me to ask a question since I can't find anything on this: Are there currently, or future plans for a 175 DE bulb that you know of that will run on today's electronic ballast? <Well, I'll be honest - no one tells me anything. I see new products about the same time you do, sometimes a little earlier if I go to The Big Trade Show but also sometimes later when folks write in and ask about it. I've certainly not seen anything lately. Might have to wait for the big report back from Interzoo in May.>
Thanks Chad
<Cheers, J -- >

Metal Halides
Greetings Anthony, Bob and the rest of the crew. <Cody here today.>Today's question is in regard to MH lighting. I've perused the various boards on WWM regarding MH lighting, but sadly, the more I read the more confused I get. My 75G reef has been up for one year as of this week. All is well thus far. I have been going with softies (xenia, polyps, leathers, etc) with the exception of a couple of open brains (trachys). My wife has been insisting on a clam from the time I set up and cycled the tank. I explained to her the need for more intense lighting and she has finally broken down and given the okay for me to procure the halides. Through the drygoods forum at RC (can I say that?) <Of course, I spend tons of time there myself!  They are a great place for info with many different opinions.>I found someone who was upgrading his system and letting go of a pair of 250W moguls w/spider reflectors, ballasts, etc. He is including 3 mo. old (so he says) bulbs but isn't sure what brand they are. He says the lighting is a bit on the yellow side. First question is, what brand and/or type of bulbs would you recommend. <This all depends on personal preference.  Every one has different opinion and you sill have to go check out some tanks with different bulbs.>If I use bulbs with a bluer hue, should I still run actinics or will the MH bulbs over-ride them? <If you use a very blue bulb like XM's you shouldn't need any supplements but again it all depends on personal preference and is a trial and error kinda deal.>Currently, I have a Coralife 48" fixture with 2 65W 10000K and 2 65W Actinics plus 3 additional 65W 10000K in a home-made set-up. If Actinics should be used with the halides, I figured I could use the home-made set-up to house them. Next, in going with the spiders, what about the lack of any type of UV filter on the fixture? Is this something that needs to be addressed? <I would definitely put some type of UV filter over these.>Finally, how close (or far) should the MH's be mounted from the top of the tank, and if I do use the PC Actinics, should they be mounted lower or at the same height as the MH's? <MHs should be about 8-10 inches away and the actinics can be mounted closer.>Oh yeah. One more thing. Should I move the corals to a lower level in the tank and gradually move them up or just begin using the Halides on a shorter cycle and gradually increase the time they are on? <Definately, I would move them to the bottom (the brains should already be there) and gradually move them up so they can adjust to the new lighting.>Thanks once again for all of your help. I look forward to hopefully meeting some of you guys this June in Chicago.<Thank you for writing!  Don't know if I'll make it but there will be quite a few of us there!  Cody>
Greg
Berkeley, IL

Metal Halide Bulbs 2/9/04
This email is for Anthony if possible.  Anthony, I am a big fan.  I really enjoyed your book of coral propagation.  
<aw, thanks kindly. Its redeeming and inspiring to hear my friend>
Are you going to do a continuation?
<yes... its my priority right after I finish the NMA volume 2 "Reef Fishes" this year with our friend Bob>
My question is concerning bulb choices for my 75Reef.  I have mostly SPS, but a few zoos and LPS.  I have 2X175W Ushio 10ks
<one of the best bulbs overall... perfect for this sized tank... and would have been my choice too>
and 2 URI VHO actinics.  
<good for aesthetics, but not needed for coral health (enough blue in MH lamps) and they are nearly ineffective if more than 3" off the water surface (check with a Lux/PAR meter to confirm)>
My bulbs are about 5 months old.  I plan on replacing my bulbs every 6 months or so to avoid a big shock to my corals.   
<needed for fluorescents... but not the halides. They go 18 months easily... perhaps over 3 yrs for some>
I am considering replacing my Ushios for the new XM 20ks.  I have seen these bulbs on an aquarium in Gainesville and they look great.  
<aesthetics yes... coral growth, no. Stick with the Ushios for best overall>
They appear very white/blue and really make the corals glow.  I would like just a little more "blue" than what I get with my current bulb configuration.    My concern is it will not be enough light compared to the Ushio 10Ks.  
<correct>
What do you think about the change?
<not recommended. Just get your VHO blues closer to the water or add an extra pair if you like for color>
Thanks as always for all your help. Andrew
<best of luck! Anthony>

Lighting 3/20/04
Hello,  I am going to purchase some new metal halide bulbs for my 120 gal tank  18" deep. I have 2 actinics 03.   My question is what temperature bulbs should I get 6,500K 10,000K or 20,000K or something I have not mentioned ?  I have 2 175w sockets.
<There are a couple of factors to consider.  "Warmer" lamps (lower color temps) produce more intensity and therefore better coral growth.  Some folks claim that higher color temperature lamps produce better coral coloration.   Mid range lamps like 10,000K fall in the middle and strike a compromise between the two.  There is also a major component of personal preference of the lamp color.  Some folks like the "natural" look of lower color temps and some folks like the bluish look of higher color temps.>
Should I buy both the same or two different temps.?
<Again, this is largely personal preference, but often looks weird when the ends of the tank are different colors.>
Current residents 2 torch corals, 1 Caulastrea, 1 Euphyllia divisa, 1 Wellsophyllia, 1 Bubble coral, 2 Percula clowns, 1 Pterosynchiropus splendidus, a couple mushroom colonies and all kinds of good stuff that's been growing on my rock for the last year and a half.
<Most of the corals you listed should be acclimated carefully to large increases in lighting.  Consider raising the lights up high and lowering them a few inches a week to their final location.>
Thanks again for your help!!!  Rob<Glad to!  Adam>

A VERY Bright Idea! (Lighting Upgrade)
Hi all......
<Hey there! Scott F. at the keyboard tonight>
Quick Q.
I have access for free to a 400W Metal Halide upgrade kit (the whole thing including bulb). The bulb is a 4100K bulb. If I use this along with a "true" actinic HO Fluorescent bulb, will I be ok to keep my current soft corals, zoo's and anemones happy...?
Jess Bansal
<Well, Jess, to be quite honest, I wouldn't use any bulb less than 6,500k. 4100k seems like it would be REALLY yellow! I wonder if it was not originally intended for aquarium use. However, it was not that long ago (well, maybe about 10 yrs or so) that 5,000k bulbs were considered state-of-the-art in halides! Personally, I'd opt for a 10,000k or 20,000k bulb, myself, as these bulbs provide more "useable" spectra, and just plain look better! And, if you are upgrading from either another light source (i.e.; VHO. PC, etc.) or lower wattage halides, be sure to carefully acclimate your corals to this higher wattage, so you don't fry 'em! Hope that your "bargain" works out! Regards, Scott F.>   

The Bulbs Are From Mars, The Ballasts Are From Venus (Bulb/Ballast Compatibility...) 
I just set up a 112 gal tank I haven't run for years. It has two 175 watt MH lights running off two separate ballasts. I think they were originally from Coralife some 10 years ago. One of the ballasts went bad, and I replaced it. I checked the specs, its the same as the old one, and I know I hooked it up right. I put two new Ushio 175w 10,000k bulbs in. The new ballast will start to run the light but after about 20 seconds it goes out. The other ballast is running the new Ushio just fine. Any ideas what is going on? The lighting dealer where I got the ballast doesn't have a clue. Are there compatibility issues with certain 
ballasts/lights? 
<There most definitely are. I'm not an electronic engineer, but as a hobbyist who has messed with his fair share of metal halide bulbs and ballasts, I can assure you that there are many different possible ballast/bulb combinations that won't work.> 
Is it worth spending the bucks on an electronic ballast that claims it will run any light? 
<Well, I am admittedly biased towards electronic ballasts. They are very energy efficient, and many brands will run all sorts of bulbs. They are generally a bit more expensive, but they tend to be less expensive to operate in the long run. I'd check compatibility issues with Coralife on your specific ballast/bulb combo, but I would also look into the electronic ballasts as a possible future option. Regards, Scott F.> 
Thanks for your thoughts. BTW, your site is wonderful. Thanks.

PULSE by PLUS Lighting Company Metal Halides...Are they any good? - 4/20/04
Hi,
I am looking for information/reviews on a particular brand of Metal halide bulb; 250 W 10k; for a reef aquarium application. <Well, after doing a search on Google ( I assume you probably already did this) I could not find anything on Plus Lighting Company within the first few results pages. Pulse is usually related to a start method for metal halide ballasts. I have not heard of this brand or manufacturer. Anyone out there reading the FAQs please let me know if you have this brand or know of any reviews for their products. Otherwise, I am sorry but I really can't help.> The brand name is Pulse and it is made by Plus Lighting Company. <Never heard of this brand or company> Any information would be greatly appreciated!!!! <Sorry to be of little help. I would try this in the WetWeb forum (other reef forums as well) and try a few other search engines. Good luck ~Paul>
Many thanks, Miguel

MH lifespan 5/7/04
I was given (2) 175 Watt MH German bulbs, which I've used to light a reef tank.  I recently found out that the bulbs were 3000-4000 hours old when I received them.  
<no biggie perhaps... I had a Radium last almost 5 years (useful as tested with a light meter). MH lamps generally do not sway much from their original index, and are useful at over 90% of their color for practically the life of the bulb (2-4 years for many)>
And I'm fairly certain that this is the cause of the excessive green hair algae in my tank.  :^)   
<heehee....ah, no. Not likely at all. Light does not cause algae, light in nutrient rich water causes algae <G>. Seriously, what you have is a nutrient export flaw/problem... and this is categorically very common. Improved protein skimming alone can cure your algae problem in 3 weeks or less>
I will be able to afford their (MH bulbs) replacement next month.  
<perhaps not needed yet>
Until then should I continue to use the old bulbs or should I merely use my other bulbs (two fluorescent bulbs)?  
<please do not shock the tanks inhabitants with such drastic and unnecessary changes>
I have a little soft and hard coral in the reef tank along with live rock. Sincerely, Josiah
<please do take the time to read through our extensive archives at wetwebmedia.com on the articles and FAQs for nuisance algae. Anthony>

PFO 13K 400W Bulb and Hamilton 14k 400 Watt Bulb
Considering these bulbs for my SPS/clam tank, have found little on the PFO bulb other than PFO, and of course they recommend it!
<PFO has a great reputation for quality lighting systems. I have not heard much feedback on their bulbs, however. I'd go onto one of the hobby forums to get some feedback from your fellow hobbyists who might have used this bulb>
On the 14k bulb I've read a couple articles that said they weren't impressed with this bulb. If you have any knowledge or experience with these, could you please share it with me? Thanks Shayn
<I have a friend who uses these bulbs in his FOWLR tank, and they are attractive from an aesthetic standpoint. I have not seen impressive coral growth with them, though. I'd choose a 10k or 20k Aqualine for coral growth. This is not to say that they are not good bulbs. Again, I'd defer you to the WWM Chat Forum to see if any hobbyists have experience. Good luck! Regards, Scott F> 

Metal Halide lamps
I recently went to a viewing of equipment being auctioned off by a local furniture manufacturing company that is closing their doors. There are a lot of metal halide fixtures, ballasts and lamps being offered. I would like to know if you may have any information on two particular types of lamps that I looked at and would they be suitable for aquarium? << Unfortunately many people have used such fixtures without much luck.  You can find lots of cheap metal halide and mercury vapor lights at home depot and lighting stores.  So far, most of the people who use them, use them on sumps and refugia.  I'm unaware of anyone who ended up being pleased with these fixtures on their main tank.  The real problem was finding ballasts that operated the right bulbs. >>
There were approx. 30-35 lamps marked "Optimarc Super Metal Halide Lamp 250watts". The package states that the lamp was manufactured in Germany for the Duro-Test Corp. Fairfield, New jersey 07007. There are no other markings or ratings on package.
There were approx. 22 lamps marked the same as above  but were listed on their package as 400 watts.
Any idea about how I can find out about these lamps, their Kelvin rating, or if they would be suitable for aquarium use? << Again, it sounds great, but I'd play it safe and buy a light from a local store where you can see how it looks on a tank. >> The
Duro-Test website does not even list these bulbs anymore. Can anyone help? The sale is next Wednesday and I understand they want rid of everything!!! Would these be a good item to scarf up or not?
Thank you in advance for your help,
Malcolm Ayers
<<  Adam Blundell  >>

GE 10k Metal Halide lamps
Hi, I have the chance to buy two 400 watt MH bulbs from a person on RC.com for $25 total.   I asked him who the manufacturer is and all he can tell me is that they are GE bulbs made in Hungary and they are brand new.  They are 10,000k bulbs also.  He won them at a reef club meeting and they have only been fired to see if they work.  Would these be good bulbs to use knowing what little info we have on them at the moment or should I stay with Ushio or Iwasakis?  Thanks, Jeff  <For $25, you have little to lose!  Your corals won't care much what brand they are or where they are made or even what they look like, as long as they produce enough light.  I would give them a shot, and if you don't like the color (use them at least two weeks for them to "burn in" before deciding), re-sell them to someone who doesn't care.  I would guess that they are at least as good as the Chinese made lamps that are becoming very common.  Best Regards.  Adam>

What kind of fixture, and are 5500K Hamilton's better than 10000K Ushios?
Hi I have a question if I purchase a light fixture that comes ready with 2 MH 175 watt of 5500K Hamilton's  should I upgrade both bulbs to 2 Ushio 10K
EACH, plus the 2 actinics, << I think you would like the color better if you did.  So I would go with two 10k Ushios, and two actinics. >> the fixture is ( these are the specs), how should I raise it more from my tank so that its not so close? << Well here is where you get to use your DIY skills.  I like to build wooden frames, but others use PVC.  I guess you should see some local tanks and get ideas about what will work for you. >> And should I take my
glass cover from my tank? << I like glass.  I like the idea of having glass because it is much easier to clean than cleaning a bulb.  You may want glass if you have a double ended bulb for UV reasons. >> or should I get a retrofit with the same specs as this one and send to make a canopy for my tank? thank you much.
High quality canopy with glossy black exterior and electro-white high reflective corrosion-proof finish for interior of canopy T-1 super quiet ball bearing cooling fan.
UV stabilized absorbing lens.
Optional 2nd fan for extra heat displacement. This is highly recommended for fixtures with 250W or 400W bulbs and for fixtures with 2 or more MH bulbs.
Very useful for reef systems!!!
Very versatile. You can upgrade your order to higher wattage and Kelvin MH bulbs. You have the option to chose between: STD (standard output fluorescent bulbs), VHO (very high output fluorescent bulbs), or PC (Power Compact).
Remote ventilated, enclosed ballast with 10` power cord Independent on/off controls for Metal Halide and fluorescent lights Amp quick-disconnect plugs to ease connection and disconnection between fixture and ballast
11 1/2" wide and 6 1/4" high. All lamps are included.
These are custom-built lighting systems. Please allow a lead time of 3-5 business days for assembly.
<< System sounds good.  Have to compare convenience to price. >>
<<  Blundell  >>

LFS Opinions and Publication Truth 9/13/04 (MHs, light, corals)
Good morning, guys!
<cheers>
Please push Ivan away from us here in South Louisiana and push it farther away from Florida!
<heehee... if only I could>
The last thing they need is more rain! I visited my LFS/LRS, probably the best one in South Louisiana, yesterday. I had intentions of purchasing a 6500ºK bulb for a pendant I have, and probably a 175w 10,000K setup for my 58g. They freaked out when I asked for the 6500.
<bizarre... I cannot fathom why>
Now, every book I've read, new and old, has suggested that lower Kelvin can be advantageous and economically friendly to some corals.
<exactly... it is THE best light for a majority of corals>
Information gleaned from wetwebmedia.com, the best source, IMHO, suggests the same. The owner, normally a helpful guy, tried to tag team me with a scientific sounding employee into discovering that 6500 is the way of the dinosaurs and I should learn from their mistakes and buy the 20,000K.
<wow... not only are they mistaken, but 20kK is actually not helpful for a majority of corals... that is to say - used alone, 20k K will suffer many photosynthetic corals because they lack adequate amounts of daylight in the spectrum to stimulate adequate photosynthesis.>
I asked how PAR ratings compare to the "plain-ol'" 6500s and how 20,000 is better, other than just marketing and personal preference. Grunts and mumbles followed.
<do a google search for "Sanjay Yoshi" to read some of his studies and results regarding PAR values>
The scientific guy said he wouldn't hesitate adding a 400w 20,000K to his nanoreef tank, again going in the face of anything I've read. What's the opinion from anyone over there?
<they have caught up in the hype... there is no basis for using heavy blue/20k K only... quite the contrary for garden reef displays>
I think Mr. Calfo would have something to say. I would really like the experienced, non-sales driven opinion here. Once again, thanks!
Ian
<with kind regards, Anthony>

Halide bulb preference
I almost forgot to ask what types/brand of metal halide lighting do you use and what P/C Fixtures? bulbs do you recommend? << Right now I'm using a Helios ballast to run my two 150 watt 20k lights. They are 20XM bulbs.  They are awesome color, but they just don't look bright enough to me.  I'm thinking that if I did it again I would either use the AqualineBusch 14K bulbs, or use some sort of 10k with actinic supplements. For the PC or VHO, I don't really have a preference. >>
Aaron
<<  Blundell  >>

Metal halide in Australia 9/21/04
Hi,  How much would a good metal halide bulb cost AU as cheap as possible??  Thanks
<I really have no idea.  In the US, the range from about $60 up to about $100 USD.  "industrial grade" lamps can be purchased as cheaply as $15 USD.  Simply figuring the exchange may not account for different shipping rates, tariffs, etc.  Do look for one of the Aussie marine aquarium message boards for more help.  Best Regards.  AdamC.>