Metal Halide
Thank you very much for the input!  I actually just got my metal halide pendant yesterday (I stuck w/ the 150w 20,000K), and it's wonderful!  I have it placed (as you suggested) around 7" above my tank and actually, to my surprise, almost the entire tank is well lit.  Just the very very ends of the tank are more dim (but not dark), but I don't have any corals placed on the extreme ends anyway.
I've been reading thru other forums and folks have been saying that my lights are just barely sufficient for Acro's or other more colorful SPS to survive and thrive, and that I should either 1) add another 150w (but as you also advised, I prefer not to do this) or 2) upgrade to 250w pendant.  Just wanted to get your advice on this as well...(probably since I have an opportunity to buy a blue tort or blue Monti w/in the near future at reasonable price).
Secondly, another common notion (and I think more accurate) among some of the forums I frequent is that there is no way I can have maxima clams or other more colorful (i.e. blue) clams in my tank (not including water parameter issues which of course is a huge factor as well) based on my 150w metal halides...I tend to agree, but I am not an expert in clams, so just wanted to get your advice on this as well.  Basically, I have a hard time accepting the idea of pushing any higher w/ metal halide wattage for my system b/c I already have had heat issues in the past and must therefore run my air conditioner a lot in Sunny Southern California.  I do hear reports of folks using even two 150/175watt MH pendants on even 20g alone, yet I have no idea how I could pull that off even w/ my 30g plus 20g refugium/sump.  Any input would be much appreciated!  Thank you very much again!
-Dennis
>>>Hey Dennis,
  Congrats on your new light.  I've used these, I'm very familiar with them, and I STRONGLY  suggest you put it at least 10" above the acrylic. You do not want the acrylic top of your tank over heating. I've seen more than one cracked top from this. The manufacturer suggests a height of 35cm, and there is a good reason for this. Heed the directions. I cannot say this in strong enough terms. DO NOT keep that fixture 7" above the tank! READ THE DIRECTIONS! I hope I've been clear on that issue. :) It might take weeks or months, but the top of your tank WILL crack.
  I have to say I agree that you will tend to lose a bit of color on certain SPS corals. If you are frequenting Reefs.org, then most people there (myself included, hehe) know their stuff. If you're frequenting Reef Central, then you have people that know their stuff, but a ton of newbies that hand out advice like they've been keeping these tanks for decades. Beware. Anyway, regarding the corals, nothing is all the time, and you will have to experiment. Montipora digita, encrusting Montis, Monti capricornis, Bali slimers, many Pocillopora and some acros will do just fine. Most blue acros will go brown under your lights. You lose a bit of intensity going with a 20K vs. a 10K, but the color rendition is better. Most of the nicer SPS only tanks I've seen run the 400w radiums. I normally wouldn't run anything less than a 250W DE fixture (which is what I use BTW) on a tank dominated by SPS corals. Euphyllia, (frogspawn, hammer and torch corals) will all do great in your tank. After messing with 150's for a while, I came to the conclusion that 250's are a better investment, especially for SPS and clams. However, given your tank size, I think you made the right choice. Keep in mind though a coral's light requirement does not decrease just because you are keeping it in a smaller tank. A coral that needs 250w of light under 12" of water to maintain color in a 180 gallon tank, still needs 250w under 12" of water to maintain color in a 30 gallon tank. This is a point many people don't seem to understand.  
A maxima will do just fine in your tank. I had a maxima under a 150w fixture for a long time, and he grew like a weed. Put him on the rocks, at least halfway up in the tank though. I would steer clear of T. crocea perhaps, but T. maxima, T. derasa, and T. squamosa are possibilities.
Regards
Jim<<<  

MH (DE)pendant glass shield
Hi crews,
It's been sometimes again that I didn't write in. I have been asking around in the forum but I guess I need the assurance from WWF crews.
I just went cheap recently and get a used 150W DE MH pendant. Although equipped with a 10000K BLV bulb, one thing weird is its glass shield is the frosted type and not the clear type. Will this shield cuts down a lot of light or it just polarizes the light? Or this is just good for photo acclimation? Can you give a ballpark figure on the percentage of PAR being blocked or polarized? How likely is it to crack if I change it to untempered glass? And I've also been pondering whether to put it 6" or 12" above tank.
Thanks a lot.
Wid
>>That is odd. I would contact the people who made the fixture - it should not have frosted glass, it should be clear. Frosted will cut down on PAR, but I couldn't give you a percentage because it could be anything!
>>IIRC untempered would be fine,3/16", but I would go to a glass shop and check price difference.
>>The distance from the water is really up to you. It is nice to make it adjustable so you can acclimate new corals to your lights.
>>Rich

Re: MH (DE)pendant glass shield
Hi Rich,
Thanks for your swift response. Btw just an update.
There is no brand on this pendant and I suspect that it is meant for general use and not for aquarium use, although it is fixed with a BLV 10000K. What make me worry most is the reflector might not be the best if my assumption is true. Anyway I ordered a piece of 2mm clear tempered glass shield and hopefully it fit perfect. And I also hope that it is not a probe start ballast.
Thanks again. Wid
>>No problem! Hope it works out
>Rich

Halide questions...
Thanks for response. <Kevin here this time> I really appreciate the advice.  I think I'm going with an Euro-Reef 6-1 skimmer but now I can't decide on a lighting system.  I really wanted to stay in the $300 range for a light and I've priced kits with two 175's for around $400 and two 250's for around $500.  Can this be done cheaper? <Doing it retro-fit without additional fluorescents is about as cheap as you're going to get.> Also, I've noticed a big difference in the price of ballasts.  PFO, IceCap, CSL??  Is the extra price for electronic ballasts worth it? <E-Ballasts use less electricity (less heat generation) and do a few other little things. Most use standard cap and coil ballasts so no worries.> Do you recommend two ballast for two bulbs or one that will work for both? <You need 1 ballast per lamp, most brands have a double ballast; ie 2 ballasts in one larger housing.> What is the best 10000k bulb? <Since you're going w/out actinics, I'd go w/ Ushio lamps, but unfortunately most people are very picky about their lamps...> Too many options!! <Good luck! -Kevin>

Using Mercury Vapor Ballasts
I have several mercury vapor and high pressure sodium ballasts....can these be used to cultivate macroalgae??? Thank you so much for what you are doing for our hobby in advance....
<Hi Jason, Craig here today. You can use mercury vapor ballasts to drive *some* metal halide bulbs (Ushio I believe) but that would be a lot of power used for growing macroalgae that could grow well under far less wattage. Something like a 55-65 watt power compact (Lights of America, Home Depot) or one designed for aquariums/wet locations. It won't take long to pay for the light with the power savings VS using a metal halide on a MV ballast, especially when used 24/7. HP Sodium is very red and not a good choice for our uses. Can they be used? Yes. Will you achieve savings using these ballasts? Depends on the wattage, if a useable bulb/spectrum can be obtained, and how much power would be used VS purchasing more efficient option.  Craig>

Metal halide grow lamps...
Hey Guys,
I just wanted to ask a few questions about reflectors and lights in general. My mum has a 400w metal halide light that she used to use for hydroponics a number of years ago.
<Hmmm... I won't ask what kind of "hydroponics"... :) >
It has a remote ballast by it has a circular shade designed for growing hydroponics.  Can I use this shade?
<Sounds like a typical bell pendant, should be fine.>
It would mean that the bulb would be mounted vertically. Or should I use a different reflector and mount it horizontally?
<MH lamps provide the most light mounted horizontally with a nice polished reflector behind them>
What type of reflector would suit the job? Where would you find them?
<Check out our sponsor Custom Aquatic for polished aluminum reflectors.>
I am going to use the metal halide with a 4foot 18 inches high and 14 inches wide.  I also have a 4 foot twin fluorescent that I plan to use in conjunction with the metal halide.  Will this be enough lighting for a reef setup?
<Sure. The golden rule w/ MH is one lamp per 2' of tank length. I'd mount it in the middle and see if you can deal with the dim spots on the ends of the tank.>
What sort or tubes should I use in the fluorescents and the metal halide to get a good spectrum of light?
<You should use actinics for the fluorescents. Also, it is important to note that you shouldn't use the hydroponic light for your reef. It's of the wrong spectrum and will cause heavy algae growth.>
Thanks in advance
Amon

Question on metal halide lighting 6/29/03
Hi have you heard of Sunsystems?
<sorry to say, yes... I have, my friend>
I'm getting a 400 watt metal halide from them with a socket called the industry's only custom-made 5 kv/hour socket exclusively  will the socket work with all metal halides? thanks JM
<I cannot say or recommend. I will take this opportunity to ask/advise you to consider the common abuse of high wattage halides over shallow tanks. Unless your aquarium is over 24/30" deep AND you are featuring shallow water SPS corals and clams.... I don't see the need for any brand of 400 watt halide. Best regards, Anthony>

- 3rd Halide Choice for a 6' Tank -
Hi, I am in the process of converting my 180 Gal fish only tank to a reef tank. Tank dimensions are 24" high, 24" deep and 72" long. Presently my hood consists of 2- 175 watt metal halides with 10,000K Coralife bulbs (one at each end of the tank) and 2- 140 watt actinic VHO's. The MH's sit about 6" above open water, I've tried moving them up higher but seem to lose a considerable amount of light in doing so.
<Yep, the closer (yet still safely away from the water) the better.>
Is this sufficient?
<I suppose that would depend on what you intend to, or are keeping.>
I'm thinking of adding a 3rd MH in the middle of the tank but can't decide if I should add a 250 or 400 watt MH fixture?.
<Again, that would all depend. A 250 would give you a nice intense spot in the middle of the tank for Tridacnid clams and SPS. A 400w would do the same thing, but may be too much for certain critters.>
I would like to keep Crocea or Maxima clams in the future, which scenario would be right for this application?
<Either 250 or 400 is fine, they will both work well for your application. -Kevin>
Thanks,
Vinnie

MH lamp orientation 7/19/03
I have a question for you guys,
<our pleasure and purpose here...>
I have a 75 gallon reef aquarium set up, it have been set up quite some time but I have only managed just to keep a few corals in the tank (haven't been aggressive about adding more stuff). I have recently gotten a reef bug and I am prepared to keep a full tank of corals. My current set up includes 2 175watt 10k metal halide and 2 96watt pc 50/50 bulbs. I currently have a Knop calcium reactor ( for future SPS corals ) and have a ETSS reef devil skimmer( just love those downdrafts skimmers !!!) my question is will this be enough light to keep a variation of corals and clams
<yes... easily>
and recently acquired Long tentacle anemone
<oh, no! please do not mix motile anemones with sessile corals... it is a recipe for disaster in the long run for so many reason. Keep it in a separate dedicated tank. At the very least... isolate it in a refugium to serve as a biotope display>
and also just reading some other reviews I am hearing bad things about pendant MH's, which is currently what I have.. and seems to be related to the bulb hanging vertical. is that true... I just need your opinion on my set up thanks.
<correct... vertical pendants focus light and do not disperse it as efficiently as horizontal orientation. Best horizontal and perpendicular to the long sides... and with a parabolic reflector for best results. Kindly, Anthony>

Home Depot Halides?
Hello WWM crew,
<Scott F. your Crew member here today!>
Thank you for your time.  I have a question about marine aquarium lighting.
<Sure...>
I am thinking about building my own lighting system and I notice that Home Depot and others sell both fluorescent lighting and metal halide lights, both at a much lower cost than can be found in a LFS or on the internet.
Is there any reason why I can't use these lights from the hardware store in my salt water tank setup? Thanks,
Whit Liggett Arlington, TX
<Well, Whit- lots of hobbyists think about this all the time. Sure, some of the components can be adapted for aquarium use. However, the main problems you encounter with "hardware store halides" are that they are not properly mounted or protected from the rigors of aquarium use (salt spray, water splashes, etc.). Also, many of the units come with bulbs that are of incorrect spectrum for aquarium use, or contained within fixtures in such a way as to prevent most of the desirable wavelengths of light from reaching the water. Also, many are in bulb configurations that render them difficult to use in an aquarium situation. That being said, however, it is still possible to use some of the components. There are a number of neat little compact fluorescent units and RO fluorescent units that you can adapt for use over refugia, use for special "spot" lighting effects on a display, etc. With a little creative shopping, a trip to Home Depot or other hardware places can yield a lot of cool stuff! be creative, do a little research- and have fun! Regards, Scott F>

MH lights - mounting/safety 7/31/03
Dear Anthony,
<cheers my friend>
the MH lamp is built within a lighting system (hood) of Giesemann.
<ahhh... excellent systems>
Still, if it is hangs too high, it may be seen by naked eye.
<no worries here. It has a UV inhibiting lens. The real danger was raw MH light reaching the human eye>
However, if I hang it about 20 - 15 cm above the water surface, all of the light will be within the area of the tank and it will not be possible to be seen by the naked eye. Moreover, the Geissmann lighting hood has its own special glass for UV filtering. Is it ok this way? Thanassis
<perfectly fine as it is. Keep on rocking and reefing! Anthony>

MH Lighting Options
Hello! <Hi there! Kevin here>
Have a request.  What's your opinion on electronic ballasts versus magnetic ballasts for MH lighting. <E ballasts should save you some money long term as they are more efficient (much less energy loss to heat) although the initial startup costs are higher. They will also fire any make lamp in its wattage (mogul, HQI, DE, pulse start, etc) so you don't have to worry about matching ballasts to lamps.> I read Sanjay's review but considering it's two years old I didn't know if the data would still hold true. <Sanjay's stuff is still pretty accurate> (More opinions?) I'm planning an SPS/Clam reef setup that will have about a 25" deep water column from the top of the DSB and want to use 175W 10,000K Ushio lighting (no actinic). <I'd suggest more wattage for such a deep tank; at least 250w> I currently have two Ice-Cap 175W ballasts (1 about three years old and 1(HQI) just purchased) and will be purchasing two more ballasts to light a 96" tank.  As for PAR rating of the 175s, I'm thinking the more light demanding species can be put further up in the water column, and all will be supplemented with feeding (I'm also going to install a 30 gal. refugium).  Am I on course? <You'll just have to be a little more cautious about putting high light demanding things lower in the tank, although the worst that may happen is that something browns out. I'd also be wary of dropping the higher light demanding tridacnids on the substrate due to the depth-lighting issue> I'm open to suggestion. <Since you are getting more ballasts anyways, why not get a pair of 250 or 400w ones instead? Since the tank is 8 feet long (!!!) you could easily incorporate them in.> As always, many thanks and kudos' to a great site and great crew! <Thanks much and good luck with the new lighting! -Kevin>
Eric

Cheap Metal Halide Lighting...Too Good To Be True?
Checking for some websites to buy lights....Is something like this workable for a marine tank?  
<Hmm...I'd pass, myself. When utilizing lights not specifically designed for aquarium use, you need to be concerned with the effects of saltwater, moisture, ventilation, etc. I'd pay the extra bucks and get a fixture specifically designed for aquariums..>
http://www.e-conolight.com/cgi-bin/shopper.exe?preadd=action
<http://www.e-conolight.com/cgi-bin/shopper.exe?preadd=action&key=E-hp2m17qz
> &key=E-hp2m17qz
Take it apart and make the ballast remote to sit under the tank or outside the stand...and build / buy a reflector for it.   COULD this make a decent aquarium light?  or am I dreaming...  Under $100 for a 175w MH sounds too good to be true.   (The HPS version is even cheaper if that's possible for the planted tank, obviously not for a reef).  
<Well, again- I am worried about potential "environmental" exposures...Possibly worth experimenting with, but you need to be very careful with this kind of DIY work...>
On a bit of a budget and I'd love to light all my tanks with MH if it was affordable (initial not to run) Mark
<Well, Mark- with the aforementioned caveats, it's probably okay to experiment, but I'd talk with people who work with lighting and electricity before playing with this stuff...Good luck! Regards, Scott F>

Cheap Metal Halide Lighting...Too Good To Be True? (Cont'd.)
Hey Scott
<Hello again!>
Thanks for the reply.  Seems like you always field my questions :)
<Cue "Twilight Zone" theme!>
I was thinking if a glass shield was used it would help a lot.  I don't remember seeing seals / gaskets on aquarium specific MH moguls before, as long as its moisture safe etc ... I was mainly concerned about the ballast and bulb being ok.  I assume a MH is a MH is a MH?
<Well, I suppose if it's either a "medium" or "mogul" base, and is of a standard wattage, it could work with common "aquarium" halide bulbs...On the other hand (and this is true even with some aquarium-specific ballasts), not all ballasts can handle every bulb of that wattage. For example, some electronic ballasts cannot fire 20000k bulbs, etc...It may take some experimentation on your part...>
I would basically take it apart and turn it into a retro kit.  I can see the concerns about salt etc though.   FYI if you ever have a need...I found some RTV type electrical tape at home depot.  Created a 'rubber' cap over the connections.  Pretty nice for the elements.
<Good tip! Thanks!>
I may just give it a go. Thanks as always!
Mark
<Do give it some thought; discuss the potential hazards/benefits with the manufacturer and/or an electrician- then do a bit of experimenting...It may just pay off. Please do be very careful, of course...Saltwater and electricity is a notoriously bad combination! Ha

-VHO's with halides just for color?-
If I build a hood with both VHOs and metal halides could I use the VHOs as the main source of lighting and turn the metal halide on just for looks whenever--for a couple hours a day. <I'd suggest against it, and run them at least 8 hours per day. How deep is this tank?> Hopefully saving on operating costs. I read in one of Bob Fenner's articles on UV radiation coming from MH, what type of filters do I need? <The only lamps that you need to worry about releasing dangerous levels of UV are the double ended lamps. 99.9% of the time the fixture will come with the UV absorbing glass already built in as a splash guard, but if you retrofit them you'll need to get it yourself.> Are 2 -6' VHOs sufficient and can you recommend a bulb? <If you were going to do only VHO's I'd suggest at least 4, but again, this depends on how deep this tank is. Good luck! -Kevin>
Thanks Louie

Reef Light Upgrade 12/4/03
Thanks Anthony.  Currently I have a leather, a wide spread of pulsing xenia, button polyps and a brain coral.  I would eventually like to have 1 or 2 clams.  
<this can be summarized as a medium light tank re: needs... just keep the clams in the top 12" if T. crocea or maxima>
If I did go with 1 175w fixture, how can I avoid the middle brace at the top of the tank?  Placing the bulb in the middle would make the brace right in the way.  Any suggestions?
Surfs Up! Jason
<the answer is easier than you think, my friend... don't put the lamp over the center of the tank. Seriously. There is no reefer rule book that says all lights must be placed evenly spaced and on center, and all corals must be evenly disbursed underneath in balanced symmetry. Just put the light off center... and use it to make a nifty dramatic effect... high light corals on one side... low(er) light corals on the other. Or perhaps a high rockscape on the halide side... trailing to an open sand area on the other for free-living corals like Fungiids, Elegants, etc. Use your imagination my friend. Else, get 2 100-watt double ended HQI lamps for either side of the tank. Best regards, Anthony>

- Halide Lighting Placement -
Hello
I want to put halides on my 90 gal reef tank. I have an all glass canopy and hood that has about 7" of clearance inside. I have been told that isn't enough to retrofit 2-175 watt halides and some pc actinics. <Not really.> I can cool the canopy with fans and I also have a chiller. <More a matter of roasting things in your tank with the intense lighting although the heat would still be a factor.> My other option is to remove the top and hang a fixture. My wife wont like that but tough. <Is what I would do - many options to make this agreeable with the significant other.>
The thing is, in either case I have heard I need to remove my glass canopy to make the halides effective. Is that true?? <Yes, to an extent.> I don't want to because of dust and dog hair getting in the tank. <Won't hurt anything... my tank has been getting dust and dog hair in it for years.> But if I gotta I gotta.
What is your take?? <No worries - pop a hole in the canopy and hang the lamps.>
Joe
Lakeland
<Cheers, J -- >

Lighting The Way ( Metal Halide Wattage Selection)
Hey gang !
<Scott F. hangin' with you today!>
You have been kind enough to answer my livestock questions in the past so I figured I would see what your thoughts are on a hardware question. Your advice and input to the "reefer" community is indispensable to say the least !
<Thanks for the kind words!>
I am in the planning stages of an upgrade to a 265 gal acrylic reef tank. It is 30" deep. My question is on the MH wattage. I plan on keeping misc species ranging from acros to blasto's to mushrooms (you get the picture) which are doing well in my current @ 2x175's . I am going back and forth between 3x250 or 3x400. Will 3x250 be enough for a 30" deep tank ? Is 3x400 going to sunburn the *$#* fish ? VHO's will also be in the canopy.
<Well, assuming that you're going to be keeping the corals that you're mentioning, plus some additional SPS corals, I'd go with 3 250watt halides. I like pendants, like the "Reef Optix III" by Sunlight Supply. Plenty of light for a 30 inch deep tank. Now, if you are going to be hardcore, shallow-water SPS and clams, then you may want to at least consider the 400 watters. Be sure to carefully acclimate all of your animals to new lighting conditions>
Additionally, what is the advantage of an electronic ballast ?
<Well, the electronic ballasts are quite energy efficient, burn cooler, drive the bulbs very effectively, and generally have a small footprint>
Thanks in advance. I tried looking thru your site but could not find exact answers to my questions, so I apologize if you are repeating yourselves. Thanks
Again !
<Never a problem! That's why we're here! Keep in mind that there are as many different opinions on lighting as there are hobbyists, so you probably want to ask a number of people before you buy! Good luck! Regards, Scott F.>

Throwing A Little Light On Things (Pendant Questions)
Thank you for your time and consideration,
<You're quite welcome! Scott F. with you today!>
I am in the planning stages of a small/medium reef tank. I have a 24"x24"x24" reef-ready tank which is empty and waiting. I am hoping to ultimately focus on SPS corals and a clam or two at or near the bottom, so I know that I need to provide relatively intense lighting. The relative depth and small footprint seem to be a perfect fit for a single MH light, agree?
<Each one of these seems to work on an area of about 2 feet square>
I am strongly considering a Sunlight Supply Reef Optix III HQI pendant with a 150 watt Icecap electronic ballast and an Icecap 10K HQI bulb, totaling about $300.
<I use these pendants, and highly recommend them!>
(These bulbs got very good reviews in a recent "Advanced Aquarist's online Magazine," article by Dr Sanjay Joshi and Timothy Marks, and is relatively cheap at ~ $50). Do you think that 150 HQI is sufficient, or would I be better served with a 250 watt HQI?
<Depends on the animals that you intend to keep. The 150's do a great job; the 250's are not much more (cost wise), and are a bit brighter...>
Also, I've come across a possible bargain(?), 175 watt Hamilton bell pendant with a magnetic ballast and a 10K Coralife bulb for about half the cost. Is this bell pendant sufficient to light the entire tank or is it better suited as a spotlight?  Am I better off with a horizontal pendant like the Reef Optix HQI?
<I prefer the wider spread of the horizontal RO III pendant, and the intensity of HQI...Also, those Ice Cap ballasts are really small, which is convenient when mounting them!>
I am still leaning toward the HQI combo, but I wouldn't mind saving some $$ if the 175 watt bell combo is suitable. Thanks again, gr.
<Well, if you can swing it, I'd go with the Reef Optix III in the 150 or 250 watt size...They will not let you down! Good luck! Regards, Scott F>

Metal Halide Pendant - 11/26/03
Thank you for your time and consideration,
 I am in the planning stages of a small/medium reef tank. I have a 24"x24"x24" reef-ready tank which is empty and waiting. <By my calculations that is about a 60 gallon tank give or take a few gallons??> I am hoping to ultimately focus on SPS corals and a clam or two at or near the bottom, <Very nice> so I know that I need to provide relatively intense lighting. <Correct> The relative depth and small footprint seem to be a perfect fit for a single MH light, agree? <Well....yeah...OK> I am strongly considering a Sunlight Supply Reef Optix III HQI pendant with a 150 watt Icecap electronic ballast and an Icecap 10K HQI bulb, totaling about $300. (These bulbs got very good reviews in a recent "Advanced Aquarist's online Magazine," article by Dr Sanjay Joshi and Timothy Marks, and is relatively cheap at ~ $50). Do you think that 150 HQI is sufficient, or would I be better served with a 250 watt HQI? <Actually I like a 400 or 2x250s if you could swing that? It would be ideal for a 60 gallon tank and not to mention the inhabitants in your tank. I am using a 250watt PFO HQI pendant over my 20 gallon with the inhabitants you describe> Also, I've come across a possible bargain(?), 175 watt Hamilton bell pendant with a magnetic ballast and a 10K Coralife bulb for about half the cost. <Well Coralife doesn't exactly seem to get the best reviews from the hobbyist I have talked to. But a good bargain I guess.> Is this bell pendant sufficient to light the entire tank or is it better suited as a spotlight? <Well, have it high enough over the tank and will likely light the entire tank but, I again feel this is not a sufficient amount of light for a tank as large as yours.>   Am I better off with a horizontal pendant like the Reef Optix HQI?  I am still leaning toward the HQI combo, but I wouldn't mind saving some $$ if the 175 watt bell combo is suitable. <I like the ReefOptix option but again to be safe and have my inhabitants growing optimally, I would go with 2x250 pendants or bells or whatever you could use to get adequate lighting for the inhabitants you plan to place in your tank.> Thanks again, gr. <My pleasure ~Paul>

HQI vs. Standard MH Lighting System
Gentlemen, Great read on your website!  After days of searching I have not found...what I seek - help in defining the difference between a standard MH setup vs. HQI setup.  If the info is out there, please forgive.  I am about to move my current 100gal. into 180gal. (72x24x24).  I would like to keep (some) Acropora w/one or two clams.  I'm taking my time w/decisions - so I have some time to "study" the options on lighting.  One of the current opinions I have encountered is the growing concert of acceptance to HQI lighting setups.  I had planned on using a system consisting of (3) 250w, 10,000K bulbs w/ (2) 96w 7,100K CFs.  Would an HQI system of (3) 250w HQIs be comparable?
< yes if not better in my use of both kinds of lighting I have found HQI to be brighter and you will get faster growth rates.>
I ask because I was told by a distributing company that the HQI bulbs were difficult to find/purchase and that they did not see them lasting in popularity because of this.
< false you can get these bulbs at many online retailers>
  I would not want to spend the $$'s for the HQI system if this be the case.
< I would go with the HQI hope this helps MikeH>  
I value your insight.  My thanks,  LB

MH lighting question
Hello "friendly and helpful designated WWM staffer that will take the time to answer my silly questions.."
Yet another MH question...I was upgrading my 55 gal (18 high, 12 deep, 48 long) tank which currently holds 2 x 96 watt 50/50 (10K/03) bulbs. I ordered a 175 watt MH retro kit with electronic ballast, and the e-tailer sent me a 250 watt ballast with the 175 bulb.
I though I was the wiser and told the e-tailer to exchange the 175 for a 250 instead of exchanging the 250 ballast for a 175. But as I read through the MH FAQs I get that hind sight feeling about the whole thing. Can I say overkill? (insert your sarcastic or otherwise funny comment here) Sure. 2X96 watt PCs PLUS 1 X 250 wall MH = bleaching corals in less than a year (otherwise known as well done, and a bit crispy) or 442 watts. Should I trade the build/ballast in for a 175 watt combo?
< depends on what type of corals you have or want to have. SPS corals love a ton of light, LPSs and soft do not. but if you run a high k bulb 20,000 you can keep both So either upgrade bulb or go to 175watt>
Am I over killing in light intensity for this size tank?
Also, a side question, should I use a glass barrier between the bulb and the water (like a perfecto glass cover)?
<would not hurt>
The bulb is a mogul type, which I understand is shielded for UV already. It will be 10" above the water in a closed canopy with fans). Would evaporate form moisture/creep on the bulb? This used to happen to me with NO tubes that were not shielded, they didn't get splashed, but the moisture from the evaporate caused creep on the bulbs and the sockets...< not if you have fans.>Any guidance or additional advice is welcome, otherwise I'll be scanning the rest of the site while you respond to this.
<hope this helps Mike H>
Much appreciated!
Hugo

A Light Conversation...
I have gotten great advice from you guys before and now I need some advice on arguably the costliest and most controversial aspect of my new tank.  If possible I would really appreciate Anthony's opinion on this subject, but would also like some differing views.  
<Scott F. here tonight!>
Here is my tank, about 2 months into the design process, I figure it will be done in about a year.  About 300 Gallon  84L x 24W x 37D.  A 7 inch DSB and about two inches of extra space at the top of the tank leave appx 28 inches of water.  I don't intend to have the tank filled within a year, like most I see.  Rather I will be taking my time and allowing corals to grow, while still leaving plenty of swimming space for my beloved fish.
<Great idea!>
Only 200 lbs of LR will be used, this should leave me with plenty of room for many years to watch the inhabitants grow.  Other than fish this will be a clam and SPS tank.  I am not looking for extraordinary growth, but would like to have healthy colored corals and clams that will be beautiful for many years.  The clams will not be on the substrate but will be a few inches higher.  The remainder of the SPS corals will be at all different heights in the tank.  What do you suggest for lighting?  My local fish store insists that 2 175 watt 10k Ushios on an electronically moving track will work just fine.  As long as I use electronic ballasts (icecap 20% overdriving the bulbs) and good reflectors (sunlight supply reef-optics).  I agree that two bulbs will work perfect if on a moving track (thanks for that article Anthony), but I have yet to see an SPS system of this size with this little lighting.
<The track concept is an exciting and under-utilized idea, IMO. However, if it were me, I'd go for higher-wattage bulbs, like 250 watts. I use and highly recommend the Reef Optix III pendants with Ice Cap ballasts and double-ended HQI bulbs. They are highly efficient, and really easy to use. I've had great results with Aqualine 10000ks in this configuration, and have been experimenting with some new 20000k bulbs as well. Aesthetically, I prefer the look of 20000ks, but I think that the 10000k's offer the better PAR values>
I do agree with him on the use of 3 or 4 T5s with electronic ballasts as supplemental lighting, 420nm, 450nm and possibly their 60/40 for better non-halide viewing.  If this set up will work how long should the halides be on for,  just 6 or 8 hours, or can I have them on for 10 to accommodate better viewing?
<I would go with the full 10 hour photoperiod for all of your lights. In my opinion, there is no real advantage (other than energy consumption/heat issues of burning the halides for a shorter duration.>
If you think that this is too little light how about 2 250 HQI 10k in a Reef Optix III, electronic ballast, on the same moving track?
<That's my recommendation>
I think it would be great if 175s would work, save me money up front and ongoing.
<Again, in my opinion, the cost differential between 250watt HQI's and 175watt mogul bulbs is not that great, particularly if you're using an efficient electronic ballast, like the Ice Cap. And, I think that you will see the difference in your coral growth over time.>
But I also really want all of the SPS corals with the bright pigmentation, and want Maxima clams.
<Yep-go for the 250 watt bulbs.>
Thanks again for all your hard work and experience.
<My pleasure! Hope this helps. Please let us know how things progress. Regards, Scott F>

MH without Actinics? - 1/14/03
Hi and good day, crew. <What up?> Can 20K MH be used without actinics? <Absolutely! I use 10Ks without actinics.> They are supposed to be very blue. <True.> My friend plans to install in his 300 gal FOWLR and inverts like mushrooms and zoanthids, no stone corals, <Could grow SPS as well under 20K MH if the right intensity and placement are adhered to>: 2 x 400W , 10K MH, & 4 x 110W VHO Actinics in one fixture <Unless he wants some dawn to dusk type atmosphere, I would drop the VHOs and add another MH>, + maybe 1 or 2 x175 W, 20K MH from his old set up. <Awesome!>
Are USHIO for the 10K and Aqua Ray for the 20K good bulbs? <Not familiar with the AquaRay but Ushio are fine. Sounds nice. Thanks for the question. ~Pablo>
Thanks, Bernd from Honduras

Affordable Metal Halide lamps and some questions
Dear Mr. Steven Pro,
Top of the morning to you! How is it?
<Not too bad.>
I would like to know if Kent's Phytoplex will work for my newly purchased Leather Toadstool.
<Probably not necessary.>
I perused WWM's site but could not find anything definitive on the above. Also got my PC retrofits yesterday. The animals are reacting very well towards it. However, the built-in fan for the sounds like a WWII plane hovering above my apartment!
<Sorry to hear that.>
Is it ok to remove the fan?
<Perhaps, watch your tank temperature. You do not want it to go above 82*F or swing more than 2-3*F daily.>
It's a Jalli 2X55W 24" retrofit kit / independent switches running a 7100K and a 10000K actinic blue bulb. Nevertheless, Kudos to all the folks @ WWM. You are doing a bloody great job. Please let me know how I may return the favour.
Laters, Mimi Eliza Rogers
<Have a nice day! -Steven Pro>

Affordable Metal Halide lamps and some questions
Dear Steven Pro,
How do you do?
<Very well, work went fine today.>
I went ahead, took your advice and purchased a Jalli 24" 2x55 watt PC (comes with built-in fan and independent switches for both bulbs) from an e-tailer for $187. The bulbs were 1 55 watt German-style 10,000K actinic / 1 55W 7100K. I will be getting it early next week. My concern is acclimating the corals (bubble, green open brain and brown polyps) to the new intensity. I currently have an 18" 15W 10000K actinic bulb. So this will be a huge move of 15W - 110W.
<Yes, a big change, but a big improvement, too.>
The green open brain sits high on the LR about 2-3 inches from the surface. The bubble and brown polyp sits on the 2" sand bed. Depth of tank is 12". I was thinking of running the 7100K bulb for the first 2 weeks before turning on the actinics.
<A good idea>
Photoperiod at present is 15 hours. I will reduce it to 8 hours with the PC's.
<Just in the beginning or for the duration. A normal twelve hour photoperiod would be my recommendation after a proper acclimation time period.>
Also concerned about my coralline algae being bleached from the increased intensity .
Water params are as follows:
------------------------------------------
Sg 1.025
pH 8.2
Nitrates 0
Nitrites 0
Ammonia 0
Ca 380 ppm
Alkalinity 10-12 dKH
Temp: 77-80
I am using SeaChem's Reef Calcium twice a week.
Please advice and thanks in advance.
Best, MER
<Please see Anthony's excellent article on acclimating corals to new lighting, http://www.wetwebmedia.com/acclimcoralslight.htm -Steven Pro>

Re: Lighting
Thank you for your prompt response to my question. Your comments raised a couple of other matters. Manufacturers of MH lights recommend one bulb for every 2 feet of tank length and 175 watt bulbs for tanks up to 20 inches deep I believe.
<I would use one metal halide lamp for every 4 square feet of tank surface area, one lamp per 2 foot by 2 foot area. Also, the brand of lamps plays a key part in how much actual light is emitted. One of the best tanks I ever saw had Aqualine-Buschke lamps and that tank was 28 inches deep with nicely colored Blastomussa, Fungia, Heliofungia, and others on the sand.>
The aquascaping plan I have in mind for my 6 foot long tank has 2 coral bommies separated by about 6-9 inches of sand near the center of the tank. I don't plan on having the rock touch the glass so there will also be a bit of sand between the tank sides and the live rock/coral. Would one metal halide bulb over each bommie with a couple of PC bulbs suffice?
<Depends on what you wish to grow, in particular, but yes for most things.>
Since my tank is 24 inches deep do I need to go with 250 watt bulbs (Iwasaki 6500s seem popular)
<If you intend to keep predominantly crazy colored SPS, use the 250 watt Iwasaki's. Otherwise a mix of LPS, SPS, and soft corals would be better served with the 175 watt fixtures, with good quality lamps. This is really the big issue with most people and their "need" to use higher and higher wattages.>
or will the 175s be Aqualines you suggested be ok? Also, how often do the MH bulbs we are talking about need to be replaced?
<Once per year is good. Some stretch it a little longer, but yearly is best to reduce photo shock. -Steven Pro>

Metal halide lights
Hello.
<cheers>
I know this may sound like a stupid question but I wanted to know if, There are any metal halide systems you can use to rest on top of your aquariums hood. 
<not a stupid question... but you cannot rest the MH fixtures very close to the water surface. For safely... MH need to be 9"+ off the water. Still... many people have custom canopies made with long "legs" to get the 9". If you are not handy to make a proper canopy... just consult a local cabinet maker and show him pictures of such canopies from FAMA magazine, etc>
Just like a normal fluorescent strip light. I am asking this because my 125 SW fish tank is in my basement and the ceiling is not strong enough to support lights hanging from it that are that heavy. Thank you for the info!!!!
<the lights aren't that heavy bud?! Unless you are talking about those piece of crap 400watt construction MH fixtures with the ballast on the bell. Very inappropriate for aquaria. An aquarium MH bell has a remote ballast that can sit on the floor. Such bells are only as heavy as a bulb, ceramic socket and aluminum housing... like a feather! Do reconsider my friend. One 175 watt MH 10K bulb per 2 feet of tank length will serve you well. Anthony>

MH Lighting
I'm planning to purchase & install 175w MHs over my 125g (tall) tank.  Is there any appreciable difference/benefits between vertical pendants and horizontal canopy-style setups?  Is it purely aesthetic or does one put out more light, less refraction, etc.?  I know that WWM typically recommends Iwasaki & Ushio bulbs...could I use these in a pendant or do you have to get a different bulb designed for a vertical orientation?  Thanks so much for your counsel on this!  I've been pouring over your FAQs, etc and studying as much as I can get my hands on...just haven't found the answer to this yet. John
<<Hi John, This is Craig answering while the WWM Gang is at play at the MACNA event.
Yes, there is a substantial difference in the amount of light and how it is reflected in to the tank and how much it will illuminate. The vertical pendants won't cover as much area and are better suited for spot lighting or penetrating deeper water in one spot. The horizontal types use the length and output of the bulb to your best advantage and good ones reflect most if not all of the light downward into the tank. This will give you more coverage and intensity from the same light. This is important for you due to the depth of your tank and relatively low wattage of your lights.  Good reflectors make a big difference. The brand and color of the bulb is a personal preference.  Make sure you buy the right bulb/ballast combination.  Retailers usually do well in this regard. Most MH bulbs for aquarium use a universal, they can be vertical or horizontal. Hope this sheds some light on the subject!  Craig>>

Changing from PC's to MH's II
Steven,
Thank you for the response to my questions. By the way the Saddle Grouper I have scientific name is Plectropomus laevis.
<Oh yeah! He is going to be a big boy!>
One question, I neglected to ask was how far above the tank should I place the metal halides?
<So that the actual lamp is 12" off of the surface of the water.>
My clam lives on the bottom of the tank (on 3" of sand), but the corals are about middle of the tank. I do not have live rock going high up in my tank; all the live rock builds up to about 1/2 the depth of the tank where the corals and any new clams would go, so I assume this has an affect on where the lighting is placed. 
Thanks again, Kevin
<You are welcome. -Steven Pro>

Metal Halide Lighting Upgrade
Hello, hope you had a great holiday.
<I did, thank you!>
I want to upgrade my power compact lighting to metal halide and was hoping you could help me out with a few questions before I make the investment.
<Sure>
What's the difference between a double ended and single ended bulb?
<If you take a good look at a single ended lamp and a double ended lamp side by side, you will see that a double ended lamp is the same as the insides of a single ended lamp. It is the same technology, just different packaging. A single ended lamp is a double ended lamp with its own UV shield already built in around it.>
Is one any better than the other in terms of coral health?
<No>
What does HQI mean?
<HQI usually refers to double ended lamps and ballasts.>
Should I be careful to buy a high quality ballast and what brands are good quality?
<I would investigate the writings of Sanjay Joshi. He has written several articles comparing ballast strengths.>
Ballasts seem to be sold to work with certain wattage bulbs. Can I use any color temperature bulb as long as the wattage is compatible with my ballast?
<Yes>
Is there a "best" brand MH bulb?
<There are ones that are better than others. Again, Sanjay Joshi's comparisons can be quite helpful.>
I was thinking of going with a 175 watt 10,000k bulb for my 46 gallon which is 36 wide x 20 tall, retrofitted about 10 inches from the surface. Current inverts include, leather, torch, Candycane, bubble, yellow polyps, and button polyps.
<I am not really sure that an upgrade to MH lighting would be helpful to your current inhabitants.>
Thanks for your help, Angelo
<You are welcome. -Steven Pro>

MH Lighting
Well,  I don't know if you guys have ever had a sense in the pit of you stomach that you weren't doing something right...
<yep... and I haven't bought inflatable sheep since then>
I'm glad I followed that sense and asked you!  I have changed the components to a 150 Watt double end MH with 2 40 watt actinics.  
<they will serve you very well. They are also one of the very best lights for longevity (years) and coral color rendition (great coral colors)>
I do plan on having clams and SPS corals but was not planning on keeping the tank dedicated to them alone.  
<and you can still have them easily in the top 1/3 of the tank>
I am also glad to hear that this will be adequate for either a 90 or 125.  Not to slam my local shop, but, I wonder why they have been  plugging the 250 watt all along????????????  
<its a common mistake in the industry. Sometimes by design... there is much better profit to be made by reselling industrial light fixtures rather than imported industry specific equipment>
Thanks for showing me the light (ar ar ar ar).  Thanks Anthony!
<my pleasure>
Scott who's lost his mind!
<Anthony who can't find his keys>

MH Lighting for 75 gall... sans sunglasses
Hello, I am in the last throws of set-up (kind of); purchasing lighting.  I have decided to go with 250 watt 10000K MH DIY, balanced with 2 40 watt actinics on a 75 gallon reef/fish tank.  
<yikes... way too much light for most corals kept in such a shallow tank. 175 watt halides are much better here. Actually... the 150 watt double ended HQIs would be superb for mushrooms, zoanthids, your LPS stonies and most soft corals>
I will eventually go up to a 90 or 125 because bigger is better.
<definitely not the case with lighting. Corals given less light but extra food survive and grow. However, corals given extra light and less food die of photo-inhibition>
I currently have a Trachyphyllia (spelling?) and a Candy Cane (Faviidae?) Coral under a mess load of NO bulbs.
<rather appropriate... they are low light corals. If they end up under halide, please acclimate very slowly (use my screen method described in the archives here at wetwebmedia.com>
I plan on suspending the lights higher from the tank than normal
<its a waste of electricity in my opinion and a compromise for the corals you mentioned (most soft corals in fact)>
because I went with the 250's so that I can expand into a larger tank and not have to worry over the lighting dilemma ever again...  Am I out of my mind?
<yes. Thanks for asking <G>. 175 watt halides will easily serve a 90 gall or 125 for how shallow they are (under 28"). The 250 watts really sound like a waste to me and perhaps a stress to the corals with the hope of getting a bigger tank months/years down the road. Unless you are seriously thinking about getting rid of the low light corals and getting a dedicated SPS and clam collection, please do rethink the lava making set up planned for this 75 gallon <G>>
Scott from Colorado
<best regards, Anthony>

Metal Halide Problems
I am a beginner trying to get reef system up and running...2 actinic lights and 2 MH bulbs. 1 of the MH will light for a minute. then cause the ballast to flick a few times and then go out. I have tried switching ballast with working light to no avail. This bulb was difficult to screw in as compared to other bulb. I do not know how fragile these bulbs are. Any suggestions? I hate to buy a new one but will if I have to.
<Well, here's the deal...There are a number of different bulbs that do not run on certain ballasts (for example-many 20000k bulbs). Also, the difficulty that you may have screwing the bulb in may mean that you have the wrong kind of base for your fixture! There are "medium" base bulbs and "mogul" bulbs, which fit into different fixtures. You need to Contact the manufacturers of the bulbs and/or fixture that you have, to assess what will work. Don't give up- but do read up! Good luck! Regards, Scott F>

Distance of lights off water surface
a bit more help, if you will.  I went through the FAQs and didn't find any recommendation as to how high above the tank (or waterline) the VHOs should be.  I did, however, find the recommendation on MH (namely 6"-9").  Thanks in advance.
<agreed and correct about metal halides (MH)- 6-9" for 150-175 watt. For all fluorescents... never more than 3"off the surface (max). Light intensity is severely reduced on these lamps as you increase the distance off the water slightly. Best regards, Anthony>

Lamps off the water...and Foghat tunes in my head
did you intend to qualify the MH height as limited to 150-175W?
<yes, my friend>
What about if they are 250W.  Would it be higher?
<likely yes, but pending your species selection and the presence (or not) of a lens filtering the light. 250 watters could be towards 12"... really a wide range of possibilities, but 10-12" commonly for spread of light if not much else). Kindly, Anthony>

MH lens covers
Seems to be a song I'm not familiar with.
As for the lens filter, I'm not clear.  It seems many people don't use it, but the occasional horror stories lead the cautious to recommend it.  I note in many places Bob Fenner notes (with disdain, it seems) that lens covers reduce light and distort the spectral quality.  I wonder what he would personally do.
<If the manufacturer supplied them (lens covers) I'd use them, but add to the weekly maintenance to remove and clean (with all turned off, cool to the touch) and replace them. The situating of 250 watt fixtures at about a foot above the water is about right. Above all, take care not to touch or splash water on these light fixtures/lamps when they're on. Bob Fenner>

Re: canopy and light design
Thanks.  I'll infer from that if the fixture did not come with a cover, Mr. Fenner would not add it.
<That is correct. Bob Fenner>

UV Shielding
Ok, this is probably a foolish question, but what the heck, I don't know the answer and have not been able to find it in the FAQ's.  I just got a PFO MH dual bulb ballast (175 watt) and I have been reading about the UV radiation for MH bulbs.  
<actually... UV comes from any type of lamp to varying degrees.>
I read that the bulbs have some sort of UV protection in the form of a coating, is this correct?  
Hmmm... sort of but not such that the UV is blocked completely. MH lamps have a tube within a tube>
When a shield is mentioned, what exactly are we talking about.
<just a piece of glass or acrylic between the lamp and the water. It doesn't take much to knock our UV>
There are no specific "UV Shields" that I can find, are we just talking about an acrylic cover on the tank, or glass maybe?
<exactly>
Also, if someone is sitting in front of the tank looking up (through the water, canopy closed), can this do damage to a persons eyes???  
<not at all>
It would be a shame to have my tank all set up, then go blind!
<no worries... just view it till you need glasses <G>. Anthony>

UV Shielding
Do I need to use a UV shield under the MH's? I figure I do but have no idea how to shield Spiderlight reflectors. I assume from looking at thousands of pics online that many do not bother to shield the light. What's your opinion on this?
<beyond protecting hot lamps of any kind from water splashing and salt creep... the UV shield is debatable. Some corals need maximum exposure to UV light for color if not health... other corals will suffer under excessive UV. My advice is to start with simple lens or shield. A plain glass canopy on the tank top will do this for you very fine. If after the dust settles and some months go by, you can experiment with removing half of a quarter of the lens and letting more UV in (through screen or grates). As you might guess... shallow water corals are better adapted to handle UV. So if you keep SPS and clams... you may not need a strong filter of UV. Best regards, Anthony>

Amped!
Hey Scott,
<Hey there!>
Thanks for the nice reply.  I learned a lot thru this process.
<So much to learn...more and more every day for me!>
One more question.
<Sure!>
I'm trying to calculate the amperage usage on ALL the electrical equipment and gadgets on my tank, as I don't want to overload my circuit breakers.
<Done that before! Not Fun! Good idea!>
My question is this:
For example, my MH ballast says it's 250 watts (2.3 amps maximum input)
That's just the ballast amperage?, or is that also taking into account the 250 watt MH bulb as well?
<The ballast...>
Am I to assume that the ballast draws 2.3 amps at 250 watts, and therefore the MH bulb also draws the same amt of current?   So the ballast and bulb = 4.6 amps of juice?  Or is the 2.3 amps written on the ballast, the TOTAL draw on both the ballast and bulb?
<Yep!>
Gracias, Steve
<Any time! Regards, Scott F>

Reef Lighting 2/8/03
Ok, one last question. I called the local lighting supply store and asked them about metal halide lighting. They quoted me on a mini self enclosed 175W (ballast inside and UV glass shield)) from Hubbell (MIC-0175H-338). Comes with 5500K lamp for 125ea. Is this a good deal and how many would I need over a 125 gallon FOWLR tank?
<Tim, after a string of e-mails, bud... I'm not sure what more to say. My recommendations are still the same:
I would not use DIY lighting for fear (or without confirmation) of compatibility issues with aquarium lamps in industrial fixtures. My recommendation for aquarium lamps is 50/50 (fluor)/10K halide colors. The 5500K lamps mentioned above are too warm colored... and often contribute to significant nuisance algae growth. I realize your desire/need as all of us to save money and get a good value here... but 12 NO lamps or industrial 5500K halides will not easily (if at all) keep the cnidarians you are likely to want>
I would like to retrofit them along with a few NO lamps with Actinic bulbs in them.
<a bad mix in my opinion... either the NO's will be too weak and useless on a deeper tank suited for halides, or the halides will be too much on a shallow tank suited for NO fluorescents>
However my Black Seal 125 Gallon has a thick strip down the middle that blocks a lot of the center pendants light if I go with three lamps. Seems like a waste.
<agreed... as per the past rec', if 150 watt 10K HQIs are not an option, then 175 watt (10K Ushio, or AB) halides mounted horizontally (never pendant) with a spider reflector (parabolic). All of the latter can be purchased piecemeal at various online suppliers and perhaps some of your locals. The reflector is cheap ($15-25), the ballasts are only about $40-60 each and the sockets, harnesses, etc are mere dollars. Else its bite the bullet for a finished kit, or stall on keeping the light needy inverts>
I need your input here before I pull the trigger. Thanks!
Tim
<best of luck, Anthony>

Styrofoam and MH bulb orientation.
Hi Crew.  
Saw something in your Daily Q&A that made me think.  I just finished building my stand for 180 gallon AGA to upgrade my 90 gal. reef.  I see that some people use Styrofoam on their stand to "smooth out" any imperfections.  Could you do this for glass aquariums too?  How thick should it be?  Does the Styrofoam compress much?
<I use 1" sheets. Sure, no reason you couldn't. It would compress a little more under the plastic frame, but no, it doesn't compress enough to be a concern. The whole idea is to spread the load out, instead of over any imperfection, which it does perfectly.>
I have been using weather striping around the frame.
<Another popular choice for glass.>
Also, for the 180 I have 3 250 MH with spider reflectors.   I was going to mount the bulbs parallel to the length of the tank.  But one of the crew said they must be perpendicular to the length, as if pointing at you if you are looking from the front in.  I have my current bulbs parallel to the front on my 90 gallon and my SPS and clams are doing very well.
<Hmmmm, me too!>
Will I get better reflection of light into the tank by placing them perpendicular?
<I don't think so. The spider reflectors are designed to reflect the most light down using the parallel facets of the reflector. Using them parallel will lengthen the area they cover and the reflector will is designed to limit the side reflection and aim it into the tank, so running them perpendicular would shorten their coverage in the length of the 180 and bleed light out the sides....not as designed.  Go parallel (with the length of the bulb and reflector parallel to the length of the tank). >
Thanks for all the help and the great site!  Keep up the good work.
Brad Stefanko
<Thanks Brad, keep em' coming!  Craig>

Light/Reflector positioning 2/28/03
I was going to mount the bulbs parallel to the length of the tank.  But one of the crew said they must be perpendicular to the length, as if pointing at you if you are looking from the front in.  
<exactly correct... horizontal and pointed at you (this maximizes distribution of light in the tank)... and further more, these bulbs have an inner glass tube that has a small nipple on it which usually must be oriented face-down as I recall for optimum burn/bulb life>
I have my current bulbs parallel to the front on my 90 gallon and my SPS and clams are doing very well.
<its not a matter of doing well... be simply getting better/more light and lamp life>
Will I get better reflection of light into the tank by placing them perpendicular?
<In my opinion/experience Yes unless you use a specific brand of reflector engineered to work otherwise>
In the response I got from you on the placement of halides, you mentioned that they should run from front to back of the tank, like a T.  
<correct>
Since these are completely different responses, I wanted to know if this is just to different opinions, or did I misread something.  
<either will work well... the reflector style (engineered parabolic or not) makes the difference>
Does it have to do with the size of my tank, 90 gallon 48" long x 24" tall x 18" wide?  I just want to be sure I am doing it right. Thanks again. Paul
No worries... simply heed the reflector mfg recommendation or do as I have suggested above if you use a DIY reflector. Anthony>

MH lighting and custom hood.
I have a 60 1/2x18 32deep with 4" crushed coral base 200lbs primo Fiji rock some soft/hard coals urchins, mushrooms, anemone, quite a bite of vegetation.1 1" red abalone didn't know it survived warm water still kicking need to build a top for tank. Daughter keeps putting scuba Steve in tank have glass top don't stop her. so my quest on is what would you do for lighting. Have a Solar Lighting Systems 6' to long 4 tank, with 6 55wat VHO fluorescent. I have access to any type of halide from 175-1000wat. I was thinking of putting 2 250 5500k metal halide and put my 6 55wt all aqua lux in custom hood. Or ma by 4 175wat halide. how high should I place lights from water going to put a 1 piece glass piece in hood with 3 squirrel cage blowers to removes heat. Have all types of interstitial ballast that will work. what is your option on ballasts. should I spend the money and get good ballast like a ice cape or something like that. Have all the ballasts and hook ups in any size to fit a army of tanks. Just need to by special bulbs. Or will the regular halide bulbs work didn't know the cal. on bulbs. have high preacher sodium, mercury vapor liquid cooled&non liquid cooled exa. all interstitial grade. Dad is electrician & has stocked pilled. What would you do?????? I know that probably going to have to buy bulbs, no problem just need to know how height to place off water .plan to have major reef tank. All I know is have to build top to keep hands out so mite as well do it all at once even if not ready yet always leave some lights off for now didn't really want to buy more VHO cost to much. my light was $450.hopping to use what have stocked pilled would like your opinion on situation....
<OK, I see 4 questions here, 1) What ballast to use, 2)Distance of MH from surface, 3)Wattage of bulbs, 4)Temperature (K) of the bulbs. If this is incorrect, let me know. Here goes, 1)The obvious answer is to use a ballast that will properly fire the bulb you get. Not all ballasts will fire all bulbs. Check with the manufacturer. As far as brand is concerned, I have seen ballasts from $40(US) to $200(US) You will have to look at the pros and cons of each and decide 2)8-10" is recommended for Metal Halide and as close as possible for the fluorescent. 3)A 32" deep tank (28 after substrate) with SPS and anemone would benefit from 2 250W bulbs. 4) 5500K will not do. Go to at least 7100K or even 10000K. Ushio and Aqualine/Buschke (AB) are bulb manufacturers recommended by many. BTW, keeping corals and anemones that require such a wide range of lighting needs (corallimorphs to SPS/Anemones) will be very challenging. You might want to rethink your livestock list. Don>

Metal halide fixtures (02/20/03)
Hey I would like to know how much would a metal halide hood cost? Can you give me some web sites with cheap hoods? Thanks
<The cost varies quite a bit, depending on how many bulbs it can uses, the wattage of the bulbs, the type of ballast... Do check out the WetWebMedia sponsors' sites for some prices. Also, the WetWebFotos chat forum (http://wetwebfotos.com/talk/) has an Equipment forum and a Local/Internet Fish Stores forum. These forums contain many, many opinions on metal halide systems and suppliers. --Ananda>

Metal halide bulbs, fluorescent fixtures? (02/20/03)
Hey I want to know if I have a fluorescent light bulb fixture how am I suppose to put a metal halide bulb in there is no screw hole? What can i do?
<You can not use a metal halide bulb in a fluorescent fixture. Metal halide bulbs require metal halide fixtures, ballasts, sockets, etc., and the hardware is not interchangeable -- even between different sizes/types of metal halide bulbs. Start reading: http://www.wetwebmedia.com/marine/setup/lighting/fixtures.htm  --Ananda>

Cleaning metal halide hoods
sorry to bother you guys for this.
<No worries, fire away>
90 gal reef tank. I have a 4' hood with 2 VHO and 2 MH lights. I have a powerhead with 270 GPH flow. I have it set so it aerates. The problem is the bubble pop and i am getting a salt buildup on the hood which is starting to dim the MH. Do I need this powerhead to aerate or is their enough oxygen with the skimmer. There is a small % of micro bubbles from the skimmer. The hood is 4.5 inches above the tank. Any suggestions? Thanks
<4.5" is very close for a MH and could be more like 8-10" depending on wattage. Salt creep is a fact of life in a marine aquarium. Cleaning the hood/lens should be part of your weekly maintenance. In answer to your powerhead question, a reef should have 10-20x turnover in GPH for a reef depending on inhabitants. That would be 900-1800GPH. This would include all powerheads and skimmer flow. Don>

Cleaning metal halide hoods
thanks for responding. The MH bulbs are 175 watt 10000k. I was told by LFS to raise hood 4-6 inches. As far as the powerhead can it be lowered in the tank so that it is only circulating water or should it be set higher in order to spit out o2 bubbles.
<If you are having trouble with low pH, the additional aeration would be beneficial, otherwise, as per above>
Would the MH and to VHO 125 watts stress small percula clownfish. Lights are on 6 hrs per day.
<Shouldn't. Again, I stick by the original reply, MH 8-10" above the surface.  Don.>

MH vs. VHO Lighting
Hello and good day to all the crew.  I also want you all to know that your service to this reefkeeper is very much appreciated.  My question is about lighting.  In terms of energy saving, which lighting setup is more energy efficient, dual metal halide 175 watt powered by a PFO ballast or 440 watt VHO system powered by a IceCap ballast.  Again thank you so much for your time and knowledge.  Travel well and happily, Timmy Nguyen
<Well Timmy, this is actually more complicated than it looks, akin to comparing apples and mangoes!  MH produces more light per watt/KWH, however, your inhabitants needs, color rendition/appearance, and actual power used by the PFO/Ice Cap ballasts should be factored into your question. The PFO magnetic MH ballasts/175watt MH system will use 350 watts and produce a ??? given light output, the VHO system will produce ??? given light output but use less than 440 watts electricity. (See Ice Cap or Champion lighting web sites for comparisons and actual wattage used).  It also depends on the MH bulb used.  It is generally accepted that MH is more efficient than fluorescent lighting for a given output, but as you can see there is more to consider.  Also look into electronic ballasts for MH lighting.  Hope this helps...Craig>

More light for the tank?/possible mantis (03/12/03)
Hi everyone!
<Hi! Ananda here today...>
I have been working on my second reef tank for about ten months now. I have had very good luck with my soft coral tank(4 years) so I am now going to try a SPS tank. This one is 48X24X18(90G).  I built the hood with three sockets for A future addition of a 250W Iwasaki. The light hood has two 175W 10000K metal halide lamps plus two VHO actinics. I am trying to strike a balance between color AND growth. Would the 150W Iwasaki be enough or would another 175W 10000K be more appropriate?
<Whoops... you mention a 250w first, then a 150w, then a 175w... each of these bulbs requires a different ballast. Do you have the ballast yet?>
The bleaching of the corallines is an issue with me, because I believe the corals will need the light. Should I add this light to the cycle now?
<No need to add the light when you don't have corals that need it...unless, of course, you read by tank light.>
I added the live rock back in September, and I probably won't begin stocking until May. I almost broke down and added a small school of green Chromis, but on one of my late night "safaris" I think I spotted A mantis shrimp possibly Gonodactylus platysoma (photo on blueboard.com) so I broke down the Q.T. (I will wait and watch).
<I would be setting up the QT to hold the mantis! They are cool critters. Even if you disagree, there are many people who would love to care for your mantis. Do check out the WetWebMedia site and WetWebMedia chat forums for discussions on how to catch and remove these critters, as well as how to keep them or where to sell them!>
The few snails and crabs seem fine.
<Keep a count on them...will help determine/confirm your species diagnosis.>
The water parameters are ammonia, nitrite, nitrate, and phosphate are not detectable. The salinity is 10.25, alkalinity 4.5 m/ltr., and calcium is 450. The water is changed every week at 6%.
<Sounds good.>
I would also like to thank Ananda and one other (maybe Anthony by the sounds of the humor maybe not) for your most recent responses.
<You're welcome... not Anthony, since he always signs off on his... sounds like one of the guys on the crew didn't want to get caught/blamed by your wife in case of your untimely demise!>
YES, I am the guy who spilled skimmate all over his living room carpet. The wife did not kill me (yet)! She just keeps asking me "When are you going to put fish in that d&%m thing?"
<Ah, the cry of spouses of hobbyists with new tanks everywhere... I would suggest you add a couple of clownfish-shaped food clips and point to them next time she asks.>
Thank very so much again Ben.  
<You're welcome. --Ananda>

HQI Ballast 3/14/03
Anthony, I can get an electronic Blueline e-ballast to run a 150 watt HQI bulb for about the same price as a PFO HQI ballast.  Which in your opinion is the better buy?
<I have no personal experience with the e-ballast for having been steered away by independent consumer tests/reports that demonstrated that they were "mis-representing" (overstating) their efficiency/benefits. I also live by the mantra that good things are seldom cheap and cheap things are seldom good :) Anthony>

Throwing Some Light On Things!
Bob,
<Scott F. on call today>
What is the difference, besides the wattage of, a double ended 150 watt HQI 10,000k metal halide bulb and a 175 watt screw socket 10,000k metal halide bulb. I know there are different types of bulb
manufactures out there but I am more concerned with the difference of the two examples above for a more generic comparison. I am just about ready to make the investment into one of these two types of bulbs and fixture combinations. I am trying to get advice on the pros and cons of 150HQI vs. 175 screw type bulbs and the differences if any.
<Well, there are a lot of schools of thought on the relative merits of each bulb. HQI bulbs require electronic ballasts, pendants with glass lenses (as these bulbs are not UV shielded, like mogul or medium base variety bulbs). I have read a number of studies that imply that a 150w HQI in a well-designed pendant (I use and really like the ReefOptix 3 by Sunlight Supply), can yield a higher PAR value than some 400w medium base bulbs...The implication here is that if you combine a good ballast, a fine pendant, and a quality bulb (such as the Aqualine 10000k or Ushio), you can have the PAR value of a higher wattage bulb, with greater electrical efficiency. On the down side, it seems like there are fewer bulb choices of bulbs in the HQI format, as compared to medium or mogul base bulbs-but this is changing all the time!>
The tank is being made and will measure 72"Lenght X 22" wide X 20" height acrylic reef tank. I am planning the placement of two fixtures above this tank at a height of 12" for the reef tank with soft corals. Any suggestions would be helpful. My standard 125 gallon glass tank did not survive the move well from NY to AZ
and so I am forced (oh well, my wife thinks my friends and I planned this so I could get a bigger tank) to have a bigger tank made, this time lighter for sure with better measurements than the standard 125gallon. Thank you in advance on this issue I have,
Sal
<Well, Sal...On my 150 gal reef, which measures 72x24x20 (shallow), I use three 150 watt HQI pendants (the aforementioned Reef Optix 3's), mounted 6 inches off of the water surface, with Ice Cap electronic HQI ballasts, and I have been thrilled with the results on my corals...Hey- that's what I like. You may find this a lousy setup...or you may love it! It's so subjective! Do a little research and get some opinions from other hobbyists on the WWM forum, and make your decision! It's a fun process-but a bit annoying, until you're finished! Good luck! Regards, Scott F>

MH lighting
Hi guys how are ya?
<Hangin' in there!>
Question for you I have a 250 watt PFO dual ballast system, I was wondering if I can run 175 watt bulbs instead of 250?
<Um, you mean on dual 175 watt ballasts, right? LOL! NOT on the 250 watt ballasts!>   
Here are the specs on the tank. 72 gallon, housed are soft corals and anemones. I am also wondering if two 36 Inch actinics at 40 watts would be enough with this combination? Also what Kelvin bulb rating do you recommend for this size aquarium 5500K 6500K, 10,000K recommended for this ballast are the Iwasaki 6500K but is that enough. Thank you, Stan N.
<Although you don't provide tank depth, it is likely a standard tank. You are on the line regarding wattage for about 22"-24" of water. You don't mention the type of Anemones either, which will have some bearing on light needs. I would use AB 10K bulbs for color rendition. You may not need the blue in this case, it's a matter of preference.  If your inhabitants have grown accustomed to the higher wattage light and they are thriving, I wouldn't change it.  Craig>

Reef On The Rise (So Are Nitrates!) and light fixture query
Hello
<Hi there! Scott F. with you today!>
I am building a new canopy for my 55 gallon tank. It will house 2 175 w MH with Ushios and a 55w actinic power compact. My question is, should I have any glass protecting the bulbs from splash, and how high should the halides be off the water?
<Well, lots of opinions on this. The height depends largely on the types of animals that you will be keeping, but as a general rule, I would mount halides anywhere between 8"-16" of the surface of the water. I'd be conservative and go for the cover glass - perhaps compensating by moving the lights lower in the canopy>
Also, I am switching over from all fish to a reef, I had 65 lbs of live rock and a tomato clown in this tank, I have a sump with 10 lbs of miracle mud with bio balls in the water. I cannot seem to get nitrates under 40ppm. I do regular water changes, the tank has been set up for about 2 years. Thanks
<Well, if you are using the "Miracle Mud", I hope that you're growing some sort of macro algae, which is an integral part of this filtration methodology. Do try some macro algae, if you aren't using any already. Check out your source water - Is it RO/DI, or does it have high nitrates to begin with? Also, I favor protein skimming in every system, even the "Miracle Mud" system..  Do a little reading on the WWM site under "Nutrient Export" and you'll come up with lots of good ideas to get that nitrate down. Good luck! Regards, Scott F

Metal halide cover
hello, <Hi Eric, PF here tonight> I am building a new canopy for my 55 gallon tank. It will house 2 175 w MH with Ushios and a 55w actinic power compact. My question is should I have any glass protecting the bulbs from splash <I'd say yes, and as UV filters too.>, and how high should the halides be off the water? <10" - 12" is standard from what I've read/done.> Also I am switching over from all fish to a reef, I had 65 lbs of live rock and a tomatoe clown in this tank, I have a sump with 10 lbs of miracle mud with bio balls in the water. I cannot seem to get nitrates under 40 <Yipes!> I do regular water changes, the tank has been set up for about 2 years, thanks
<Well, MM should be used with a nutrient export method: i.e. macroalgae. The official Ecosystem method advises Caulerpa, but I'm not fond of Caulerpa as it causes to many problems. IMO Chaetomorpha is a much better choice. You didn't mention a skimmer on your system, also you might want to look into using a DSB to help reduce your nitrates.>

Metal Halide Lighting
Bob,
First, I need to thank you, as my tank has flourished under your sage advice. I've progressed from a FOWLR to a true reef tank with anemones and soft coral. 
I've just recently added a sump (what a great addition, it took my UV filter, temp monitor, and thermometer out of site!) and a 175W metal halide fixture and ballast. My LFS is still awaiting a shipment of metal halide bulbs. 
My question to you is this. I went to home depot where they have in stock 175 watt metal halide bulb (the Philips lighting co). There is no specification as to Kelvin. I was wondering what the difference is between this bulb and those sold at FFExpress or the LFS? Your input would be greatly appreciated. 
PS. I have read every archive on FF express and have learned more about reef keeping than I would have ever imagined!
Thanks, Jim
 >>
Wowzah, high praise indeed! My friends compare my cooking skills to sage-brush, but I always imagined this was different...
Well onto your MH query... it may well be that the HD unit is of service. Get the "stock number" of the product and take an e-mail stroll over to Phillips website... all will be revealed... or better put, awakened to your consciousness, by your efforts.
Bob Fenner

MH Fixture Placement
Hi bob, I just emailed you and forgot to ask 1 thing...I told you I have a 55 gallon high tank, so its not as wide as a normal 55 gallon but higher. I was thinking about getting a metal halide instead of the additional 2 55watt pc, but the tank has that strip of plastic down the middle, which is where I would have to hang the metal halide above, directly in the middle, in this situation, I thought that too much light might be blocked, am I correct in assuming this?...would the metal halide combined with the 2 55 watt pc I have now be that much better than just adding another set of 2 55 watt pc?...sorry for emailing you twice.. and thanks again....Jeff
>>
You could place the MH or two off to the side(s)... no need to completely illuminate the whole system the same... functionally or aesthetically...
Bob Fenner

Metal Halide lighting
Robert
I currently have a 110 gal fish only tank with 1x48in 50/50 florescent, that I would like to turn into a reef tank (i.e. live rock, corals etc). I have a 400 watt metal halide lamp that I am planning on adding when I make the switch over. I will be using a fan to dissipate heat from the tank and I have about a dozen snails to take care of at least of some of the microalgae plus I have recently added a refugium (built out of a 5 gal bucket). What other factors might I have to worry about when adding this dramatic increase in light, and possible remedies?...Thank You....
Nick
<Very good question... and a shame you don't have two 175 watt units instead... very hard to get much spread over the size, shape of this system with a single pendant. By increasing photosynthetic rate via increased light intensity, you need to concomitantly elevate alkalinity and biomineral content (or do what needs to be to keep elevated...), guard more critically against pH swings... likely add Carbon Dioxide in some fashion... be more diligent, regular about testing, supplementing, cleaning in general... More specifics as your system develops and the situations arise. Bob Fenner>

What Size/Wattage of MHs?
Hello
Hope you can steer me in the right direction. I am going to purchase another lighting system for my tank(48x24x24.The lighting I currently have now is the 4 96wattpc"s. When I purchased these last year , they said I would be able to keep SPS corals as well as clams with no problem. As I am finding out you can't. The watts per gal. is only 3.2. 
<And the tank quite deep for CF lighting use...>
Needless to day I am not happy , so I am going to purchase a halide , actinic system. custom SeaLife). I am a little confused about the bulb wattage though. Some folk's say that I could use 2 175watt halides and be able to have all the maximas and Croceas my heart desires with no problem. On the other hand , I am told to purchase the 250ewatt halides because my tank is 24inches deep. Can you please clear this up for me?
<The 175's would work, but the 250's would be better... there are even people who would encourage 400 watters... and I've used 1kilowatt fixtures on two foot deep culture units... The balance of waste heat production, electrical consumption, driving photosynthesis, algae problems, matching biomineral, alkalinity, CO2... All have to be figured in, dealt with>
I am hoping to purchase the proper lighting (this time) , and don't want to screw it up ,as you know these halide systems are very expensive. The set up I want is a little shy of $ 1000.00.Hope you can help me with this , because I can't afford to do this AGAIN. As always thanks, and take care. PS. I can't wait for your new books!
<Me neither... and do go with the 250's... IMO these are the best choice for you, for the organisms you want to keep, what you want to do with them, and how much trouble you're likely to cause yourself. Bob Fenner>

What Size Metal Halides?
Hi Bob
Hope you are having a fine day today. I have a question on lighting. My tank is a 120gal the size is 48Lx24Hx24W. My present lighting is the 4 96watt pc's. I am going to purchase a halide set up so I can have a few SPS corals along with a few maxima clams. As for the dimensions for my tank should I get the two 175watt halides or the two 250watt halides ? I will also have the proper actinics added.
once again, thanks for your time, take care.
<If it were me, my system, I'd go with the two 175 watters... some folks would opt for the higher wattage ones for sure, but they're unnecessary, will elevate your tank temperature and electric bills too much... 
Bob Fenner>

Metal halide lighting
good morning, evening...
<Or afternoon>
if you find some time...could you give me some info on the following...
we are upgrading our system and need to get a new metal halide unit to successfully keep clams and hard corals such as Acropora. our new tank will be 5ft long by 22 inches high and 18 back to front.
our present unit is a system 2000 double 150w with 2 actinics. I believe it was a mistake, too little light.
<Yes... you could easily use two, three times this amount of illumination>
So, as I am in UK, all what I have come by are Arcadia and system 2000 units.
I've also been informed that apparently the double 250w arcadia light overheats and since causes the unit to melt?
<Yikes. Poor engineering... what does the company say to this?>
what other brand would you recommend, and if not in the UK, is it possible to order it from the States? or anywhere else in Europe?
<Do contact the folks at Tropic Marine Centre there (the link/URL is on our site www.WetWebMedia.com links pages, and ask their input please>
let me know what is best.
as always a BIG thank you from Stefi in London.
<You're certainly welcome luv. Cheers, Bob Fenner>

175 MH
I just finish reading most of you questions and answers on your FAQ section and am very impressed.
Maybe you could help me also I hope.
<I will try>
I have a 75 gallon tank 4 foot by 1 and a half by 3 deep.
<Three feet! You must have long arms>
And over it I had some hardware store bought MH 175 each
Someone told me that those lights were too yellow and so I went and bought some Sunbursts 10k 175x2.
Well not only does the tank look purple but a little dark the soft corals went into shock and algae growth was very bad
<Hmm, a bunch to state here... 175 watt metal halides are not powerful enough to adequately light three feet of depth of water... If you can otherwise deal with the waste heat, I would look into 250 or even 400 watt units... two fixtures. Temperature is important, as is the brand/maker of the lamps... there are less blue varieties in the 10,000 K range... You need to graduate new lighting changes to your livestock... with timers, shading of new lamps...>
Button corals were not doing well and well it looked like a disaster.
So I gave in and put the old bulbs back in and it seems that everything is calming down.
My question, what lights should I put my money into? I’m confused.
I have a couple of fish and some live rock and some soft coral what do I do now?
<Please post your "what type MH" question on our Chatforum: http://talk.wetwebfotos.com/
The many fine folks there are more up to date on what's available. Be chatting my friend. Bob Fenner>

Making Lava
Hi again!
<greetings Walter, Anthony Calfo here for Bob... either my meds are wearing off or this is the first time that I've had the pleasure to answer a query from you>
My tank size is 48w 24h 30deep, I have 2 400watt 20,000k metal halides and 4 VHO 660 Ice cap fluorescents 2 50/50 2 actinic.
<good Lord that's a lot of light! Unless you are making lava in your tank, I'm hoping you are going to tell me that you only keep shallow water SPS corals, because I can't see another reason for 2(!) 400 watt halides on a 30" deep tank. Of course, the other possibility is that you were the victim of a convincing light salesman>
My question is ....... I was wondering if it would affect my corals and fish @ all if I had the halides go off and on Twice a day, I currently have them go on 1 hour and a half after the icecaps go on, and they go off 1 1/2 hours before the actinics do. The halides are on for @ least 9 to 10 hours a day.
<although hardly natural... I'm sure the fish would adapt. And the corals would stop screaming for a couple of hours. Indeed, 9-10 hours is a bit too long for halides over most systems. All joking aside.. if you've had your system running like this with coral for more than a year, have you noticed a tendency for pigmentation of many coral species to shift to yellow or a like pale color?>
I think I would set them to come on for 3 hours and off for 2 and then back on for 4 hours. What do you think???
<it sounds like a better scenario than present. kindly, Anthony>

400 Watt Metal Halides
hi there thanks for the response No I am not making lava, Ha HA! And I am not the victim of a clever sales man either. 
<Walter, I thank you kindly for your sense of humor!>
I had my tank running for about a month now. I have Red sea xenia which has gone bonkers with the open close open close rhythm,
<unrelated to lighting...definitely a dynamic of fluctuating pH/alkalinity. I have cloned more than 10K frags of Xenia in my greenhouse in the past decade and found this to be one of the few truisms of reef aquariology>
small Acropora frag. that seems to be doing fine 
<indeed...better suited to the lighting>
a couple of leather corals ( yellow ) A green lobo. piece small <the Lobophyllia will not survive long under these lights...six months to a year max if direct. Do try to shade or filter light with an outcropping>
one huge Sinularia one small green finger coral 2 colts one may have be affected by the light,
<almost certainly... Colt Corals (Alcyonium) are deeper/turbid water>
green Starpolyps about half way in the tank and a green tip torch coral fully open. 
<same as Lobophyllia>
What can I do to maybe lessen the amount of light so my corals don't get hurt in the future 
<do not play with photo period or cycle so much... better to leave on 4-7 hours daily, but screen the canopy with a filtering mesh or like product to reduce but not block all light (like plastic fly screen). You can add layers to get the desired effect>
or maybe other thing I may put in there Like clams,, Acropora etc....... Any suggestions from a pro???
<now you are talking, bud... when life hands you lemons, you make lemonade! Clams (Blue maxima and crocea in particular) and shallow water SPS corals would be the ticket. Avoid most all brown pigmented corals (tend to be deeper water). Good coral choices for bright aquaria include Pink/Orange Montipora, Yellow Finger Porites, Goniastrea closed brain corals, Yellow Leathers and colored Porites. Study photographs in Veron's works of shallow/tidal corals and research the availability of ones that attract you. Best of luck to you, Anthony Calfo>

Too Much Shimmering!
Hello Gentlemen,
I just installed my 2 x 175 watt metal halide with spider reflectors and it is working fine except it is shimmering too much. It is to a point where I almost get dizzy looking into my tank. Is there any way to decrease the amount of shimmering effect?
<Not really. Most people consider it a benefit of MH's.>
Is this cause by the nature of the reflector or because I have so much water movement on top?
<The shimmering is caused by the ripples on the surface of your water. I would not change anything now and see if you do not get used to the new effect.>
As always, thank you very much for you input.
Cheers, Dan
<You are welcome. -Steven Pro>

Lighting
Do you know where I can get the perfect hood for the halides that has 2 sockets built in or do I have to get 2 separate pendants?
<There are various manufacturers of canopies that have MH socket with NO, VHO, or PC actinics. I know Champion sells some, look around for others.>
Wouldn't the Ushios bulbs give me a blue tank?
<Bluer than the Iwasaki's, but not blue.>
I rather have a look that people describe as shimmering like a shallow reef or does the Ushios give me that look.
<All MH's have that shimmering effect.>
I really appreciate all the help you are giving me.
<You are welcome. -Steven Pro>

MH or no?
Dear WWM Crew,
I want to thank you for your previous precise/quick responses. You guys are doing a great job! 
<thank you for your kindness in saying so!>
I have a few questions regarding switching my lighting application with the intent to incorporate it for a bigger tank in the near future. I currently have a 90 gallon reef tank for 3 years that is powered by 520 watts of retrofit power compacts (PC). My livestock are mostly LPS, soft corals, and one bubble tip anemone. I am currently considering switching to 2x-250 watt 6500K or 10,000K metal halides (MH) in conjunction with 130 watts of PC actinic. 
<forget watts....not even a fair comparison in this case... a Luxmeter at 12" will show you that the difference between 520watts of fluorescent light and 500 watts of metal halide light are night and day!!! MH penetrates deeply and that is why it is such a great deal (bang for the buck). However... 250 watt MH will bleach many of the present and accounted for LPS without a lot of work in acclimation for you. Not to mention adding the other 130 watts of PC actinic (cool looking but not necessary with even the 6500K Iwasakis other than aesthetics. They have plenty of blue for symbiotics on a spectral chart>
I am also planning to buy a 180 gallon tank in a year or two, so the MH will be incorporated with the entire 520 watt PC. I have some questions and concerns with the change to MH.
<so far sounds like this set up will be more harm than good for your livestock... still, it would be a very nice outfit>
First, I am afraid of the 2x-250 watt MH will burn my corals because some are placed very closed to the top. What are some method(s) of screening the MH light to allow the corals to adjust? Or is this too much light for the corals? 
<yes... the latter my friend>
Can I buy a 250 watt ballast, but use a 150 watt bulb for the 90 gallon tank now, and later switch to a 250 watt bulb when I buy a 180 gallon tank? The reason for buying a 250 watt ballast is because it offers greater flexibility/versatility when it will ultimately use for a 180 gallon tank, but I want to try MH now.
<even later... if the 180 gall that you pick is not deep or packed with SPS, it is still too much light. A standard six foot 180 gallon tank would be better served by 3-4 175 watt MH for sift corals or LPS which are most popular. I have no knowledge of the bulb switching although it sounds unlikely or at least scary>
Secondly, with regard to MH, I am undecided between the Iwasaki bulb vs. the HQI bulb. Are there any distinct advantage(s) between the two bulbs?
<I have seen one study that pegs the Iwasaki as far and away the best choice for reef inverts in general>
Furthermore, is there any ballast brand (PFO, IceCap, Blueline, etc.) or type you can recommend? I am researching through the differences between the standard core and coil ballast vs. the electronic ballast. 
<the benefits of electronic ballasts are a figment of marketing imagination. And I have a distinct preference to avoid one of the above named. I will say that despite early R&D difficulties, Icecap has always enjoyed an outstanding reputation for customer service. I personally have had very good experiences with them>
So far, the electronic ballast is much more efficient in terms of energy, heat, and bulb life. 
<not even close to being true by one expert I am aware of (unbiased, unpaid and very convincing>
But, I have heard some people mentioned that the electronic ballast is not a perfected technology yet. A lot of the electronic ballasts have a tendency to break down and/or not work properly. Is this true? 
<I have heard an overwhelming amount of criticisms in this line... too much to discount it. yes>
I saw IceCap have the electronic ballast that would fit my needs and I was wondering how reliable they are? Thank you for your time. Cheers,
Dan
<this is one area that I am content to say if it isn't broke don't fix it. A standard MH ballast costs $45-60, add a harness and ceramic socket and you have a workhorse that just might last more than ten years. It is old, tried and true technology). I wouldn't put my money on an electronic ballast to do that just yet or for some of those companies to be in business that long to back the warranties. IMO>

Re: MH or no MH--Follow up in stereo
Hello,
<right back 'atcha, Bub. By the way... the latest report of Bob's zany trek across Australia has placed him running amok in an enormous clear plastic hamster ball through the streets of Downtown Sydney... he says there's no better way to travel.>
It always amazes me how quickly you guys respond...the entire WWM crew's dedication to this hobby deserves much praise! 
<Grazie>
To recap our last correspondence, you are in favor of the Iwasaki 6500K MH and a standard ballast. 
<exactly... a very good all-purpose choice>
I have follow-up questions in terms of wattage for MH, a reliable ballast, and a