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FAQs about Metal Halide & Halogen Lights and Lighting for Marine Systems 3

Related FAQs: Metal Halides 1, Metal Halides 2, Metal Halides 4, Metal Halides 5, Metal Halides 6, Metal Halides 7, Metal Halides for Small Systems, Metal Halides for 40-200 gal. Systems, MH for 200 gal. Plus Systems, Metal Halide Lamp Issues, Metal Halide Fixture Issues, Metal Halide Heat Issues, MH Repair Issues, Compact Fluorescents, Regular Fluorescents, Lighting Marine Invertebrates, LR LightingTridacnid LightingSmall System Lighting,

Related Articles: Metal Halide Light, & Lighting Articles, Coral System Lighting,

Arranging a back-up safety harness on your lighting is a very good idea.

Metal halogen question Hello everybody I hope all is well. <Hi Chris, MacL here> I had a question about lighting my saltwater aquarium.  I recently got a new job where we use low voltage out door lighting with mr16 halogen bulbs. I was wondering if I could use mr16 for my various tanks fresh and saltwater. <I believe that you can but you run several risks.  Metal halogen can explode if they get wet and I'm not sure they will have the correct spectrum.> Do they make bulbs for such applications? <You'd have to talk to the manufacture about spectrums that they have. I might add though that they did use halogen in Japan but they had them elevated WAY WAY WAY off the tank.>  I haven't been able to find anything out about this and I know you have way better sources of information than I do.  Thank you in advance for any help.  <Hope that helps MacL>

Additional info on metal halide upgrade - 1/28/04 Thanks for your quick response! <No worries> I apologize, but I left out some important information.  My current VHO system is comprised of (2) 46.5" URI actinic and (2)46.5" URI actinic white. <OK>  In the new setup, I intend to use the (2) actinics in addition to the MH's. <Fine, but again, this is more for balancing the look and purely for aesthetic reasons only.> This will also be the case on the large tank, but I will put in 60" lamps. <Fine>  Also, in both scenarios I will be using a dimmer on the VHO's. <Cool>  Does this change your response in any way? <Not even a little. Is that what you expected me to say?> BTW, to answer your question of why the upgrade, it is purely for aesthetic reasons. <Really?? Expensive upgrade then. I love it! ~Paul> Thanks again, Dave

Playing With Fire? Hi, I wanted to know if I could put a HQI bulb of any appropriate Kelvin range onto a plain regular regent 300 watt quartz Halogen floodlight. Is this possible. I intend in doing this if so. Because the current bulb is far to yellow and unsuitable for a reef tank.  My name is Ray. Thank you. <Well, Ray- I'd caution against trying any unknown bulb/fixture ballast combos unless you talk to the manufacturer first. You could cause a fire- or worse! Err on the side of caution! Regards, Scott F.>

Double-Ended Metal Halide Bulbs? Hi Bob and Gang, <Scott F. your gang member tonight..> I am going to upgrade my lights to metal halide from power compacts. I have noticed in some of the online retail stores that there is a double ended metal halide lamp that I haven't seen too much of. How effective are these compared to the more popular mogul based lamps? Do they run hotter? Do they use more or less electricity? Have you ever used these type of lights? If you have how, in your opinion, did they perform? And, more importantly are they less expensive? Thank You for taking your time to answer my questions.  John <Well, John- let me start by telling you that I both use and recommend the double-ended halide bulbs. They are quite efficient, provide as much, if not more intensity and PAR than many mogul-type bulbs, and come in an ever-increasing range of wattages and spectra. The bulbs do run at a much higher temperature than moguls, but require electronic ballasts, of which there are many to choose from these days. Electronic ballasts tend to be a bit more efficient than the magnetic type ballasts. They do come in various wattages to suit many applications. Of equal, if not greater importance as the bulbs are the pendants that one employs with them. Many great models are out there for double-ended, by reputable manufacturers such as AquaMedic, PFO, and Sunlight Supply. I've seen a number of studies by serious hobbyists, such as Sanjay Joshi, which confirm outstanding results with double-ended bulbs when used in a well-designed reflector, and paired with a good ballast. Do a little research on various e-tailer's websites to see what models are available. There are a wide variety of prices, but on the whole, I'd venture to say that D/E bulbs and pendants are a bit more expensive than moguls, but worth the difference, IMO. Hope this helps! Regards, Scott F.>

Double-Ended Halide Bulbs (Cont'd.) Thanks Scott, <You're quite welcome!> A few more questions if you don't mind.  Can I take one of those metal halide pedestal lamps and convert it?  If not, why not? John <Well, that's a common question, and a lot of the answer has to do with the fact that pedestal lamps are not designed for aquatic applications: First, they are not made for moist and harsh environments. Second, they do not have reflectors to assure that light is being properly directed into an aquarium. Finally, the bulbs are generally not of any spectral quality that we'd want to use with aquariums. Best to stick with those products designed specifically for aquarium applications! HTH Regards, Scott F>

Bring On The Blues! (Halide Bulbs, That Is) One last question....For Today at least... The bulb my Aqua Medic light came with was a 150 watt 10,000 K bulb made by Aqualine <An excellent bulb!> Does this type of bulb, being that it is the only thing I can now fit over my tank, make corals fluoresce, and will it support the growth of corals and coralline algae...or is there a different manufacturer of bulb that has more blue spectrum in it? Thanks Guys <Well, the Aqualine 10000k is one of the best all-around halide bulbs available, IMO. It has an excellent PAR value, gives natural color renditions, and will definitely grow many corals. It will generally not fluoresce animals. For that, you'd want to either supplement some actinic lighting (VHO or PC is fine), or use 20000k bulbs (In fact, Aqualine just came out with one here in the U.S.). Do  keep in mind, however, that many 20000k bulbs do not create the same level of growth with corals that a 10000k or 6500k will, but the colors are pretty cool! Personally, I like the 20000k look! Hope this helps! Regards, Scott F.>

Metal Halide Bulb Options Hi all, <Hey there- Scott F. here  today!> Thanks in advance for all the answers you have provided in the past.  I am looking for a recommendation between Ushio vs. Hamilton 175 watt MH bulbs. Any insight would be greatly appreciated. Thanks, Andy <Well, Andy- it really depends upon the specific bulb that you're looking at. The Ushio 10000k bulb has a nice color, respectable performance, and a good reputation among hobbyists. Hamilton is better known for lighting fixtures, but does offer a number of bulbs. If it were me, I'd go on the WWM Forum and see what your fellow hobbyists think...Lots of different opinions out there. Enjoy the research! Regards, Scott F.>

MH selection - 01/15/04 I was wondering if you could help me choose a lamp for my MH pendent. <Well, we'll see>I was thinking towards an 250w XM 20,000k because they're cheaper,<Not familiar with XM as far as quality and reliability> but the Coralife 250w 20,000k has been more popular and recommended by everyone I've talked to, <I haven't heard a great deal of positive remarks regarding the Coralife MH fixtures or bulbs for that matter. Maybe Custom SeaLife is a bit better from a price point? I personally use the PFO 250 Pendant/HQI ballast with an Ushio 10K double ended bulb. A reliable, functional, and quality bulb in my opinion but a little on the pricey side though.> and they're much more expensive. which one would you use on your tank? <I like Ushio, Aqualine-Buschke, Radiums for sure.> also, is there any real truth that moonlights help in coral spawning? <Well, a lot more goes into the cues of sexual reproduction than lighting alone. It is a reproductive indicator, but foods, water parameters and temp can be said to have an impact on reproduction as well. Nice to have moonlights as a luxury but I would not pay for it for spawning capabilities alone. ~Paul> thanks, Zach.

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 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>

Tank lighting too hot - 12/15/03 Hola crew,     I have spent hours upon hours on your website, researching fish, clams, and many other Marine aquarium things. <Know what you mean and now I work here......oh =) Let us know when your ready to take the challenge, eh?>  I recently upgraded from a 55 gallon to a 140 gallon tank.  I just got the 400W MH lights hooked up, and my temperature soared! <Yikes> Its semi cold where I live (Fresno, CA.) and the temp can vary. <To say the least>  But the house is usually 65-70 (in the winter)  Summers here get into the 100's. <millions>  Anyway, I had the temperature at 78.3, and today I installed my new lights and in two/three hours the temp went all the way up to 82.5, and I finally just shut the lights off. <Good idea.>  I have read the chillerfaqs and am going to try a couple fans tomorrow, but not sure if this will bring the temp down, considering I am not even sure if it was done going up. <Likely not. I had a similar problem with my 250 watt MH added to my 20 gallon. I am using a dual Aqualogic controller with the heater plugged in one receptacle and a fan in the other (blowing over he water and light). Once the temp gets to a certain programmed temperature (programmed by me) the fan kicks on and once it cools the water to a certain point the controller kicks the heater on.> I would have let it go up until it got to a stable temp just so I know, but unfortunately in my excitement I transferred some of my coral over before I tested the lights! <Whoa>  Brain fart. <Happens. Know what you mean> And the lights are only about 6-8 inches from the water. <About right> Do you think fans would work for me? <Fans could easily help> Or do I need to get a chiller? <In Fresno it is not a bad idea.>  I know nothing about chillers so any advice here would be great. <Not too big of a deal but pays to read reviews and recommendations. Look at cost not only in device but also in upkeep and electrical cost to run>    Thanks! <You bet! Happy Holidays ~Paul> Phil

- Halogen Lighting? - Thank you again for your time!! First one:  Today in a fish store I saw a halogen light set for sale.  On the box it showed these lights over a fish tank, and in part of the description the company said.  Fits in wonderfully with metal halide lighting as a cheaper alternative.  These 500 watt halogen lights can be used in conjunction with actinic 03 blue metal halides, or any halide bulb, to create a beautiful well lit aquarium.  Is this true? <It will light the aquarium well, but it's not a good substitute as far as lighting spectrum goes. Would be fine for a fish-only system, but worthless for photosynthetic animals.> Can I go to Wal-Mart and by 500 watt Halogens and use these? <You can... but I wouldn't.> Sounds to good to be true to me. <It is.> And finally what do I feed brine shrimp if when they hatch there are to many to put in my display tank to keep them alive for future use? <That won't work. Brine shrimp need higher salinity water than what is in your display. Would create a toxic, stinky mess.> Thanks again Craig B. P.S. I still would like to help you guys, I want to make a donation to help keep this site up and running, but I have never been given an address or what to have the cashiers check made out to. <There should be an Amazon link on most pages that allows for a donation to our cause. Cheers, J -- >

Metal Halide lighting a 60 gallon - 12/7/03 Hi I have some minor lightning problems which I hope you can help me with. <See what I can do> I plan to upgrade to a 50-60 gal, 16-18'' high tank, in which I plan to have mainly soft corals like Sinularia, Sarcophyton, buttons and mushrooms. I plan to cover the tank with a glass cover. My choice is between buying a used 150W single ended MH, in witch only a 6500 K bulb fits or a double ended 70W MH, to which I can get a 10000-14000 K bulb. <are you sure that the 70W is for aquarium use?> The 70W is not originally for aquarium purposes, <Ahhhh> but have been used for show off lightning at a car market. <I guess these are OK but where are the bulbs coming from here?> I have the opportunity to supplement with 2x18W fluorescent. <Not necessary, but could be used for aesthetic reasons if you must> The shape of the tank makes it difficult to have more than 18W fluorescents. Will: (1) 150W 6500K + 2x18W actinic (2) 70W 13000K + 2x18W daylight/10000K/actinic <So are you saying that you are going to use the combination above?? or is it a choice one over the other. The combination above would be pretty good. Why can't you just get 2 250W pendants? Something to that affect?> or both alternatives do the job? <More than adequate for your intentions to keep soft corals for sure> If I choose the 150W MH, will it be possible to have other types of photosynthetic animals (LPS, T squamosa etc)? <Possible, but the Squamosa might be pushing it. Check with Barry at ClamsDirect and see if his Squamosas would be capable of handling your depth and lighting scheme. www.clamsdirect.com I would go for maximum lighting ( 2x 250 or 2x400 if you can afford the cost and electricity) and keep any type of coral and any other light dependant inverts you want! At least that is what I would do if I were Brian Boitano! (random South Park reference) Sorry. ~Paul> Thank you  /Anders

MH wattage and color temperature question Hi, Thanks for the quick answer. <our duty> I meant a choice one over the other, (1) or (2), not the combination. <Oh. Then I would go with the 150W> Did you mean that a 150W 6500K without any additional actinic would be OK for the soft corals? <Yep. We don't use them at the aquarium and I don't use them at home. We have well documented growth without the supplementation of base actinic use with both soft, LPS and SPS. We use a mixture of bulbs 6500 and 10000> You can buy 70W HQI aquarium lamps/bulbs in Europe, I don't know if that's common in the US.  <HQIs are available here in the US but I have little experience with 70W.> If I could afford it I would buy new ones, <Not necessarily new ones but just higher lighting options.> but if I were, there would be just cents left of my aquarium budget. <Understood ~Paul> /Anders

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

MH Lighting on a 45 gal  Hello,  I just found this site and it has been very informative, My current setup is a FOWLR 45 gallon with the dimensions of 36" width 12" depth and 24" height. This is my first system and has been up and running about a year with about 90 lbs of LR. I currently keep no corals but would like to add a few so I am upgrading my lighting. My questions are as follows here are the 3 setups I am looking at:  3 96 watt 36" power compact hood with various combos of lights.  2 - 175w metal halide retro with 10k or 20k mogul based lamps.  2 - 250w metal halide retro with 10k or 20k mogul based lamps.  If I went with the 250w halides or 175's I would also have 2 36' NO or VHO actinics for dusk to dawn effects if needed. Both the halides are retro and the power compact is a complete hood with fans, etc. I would construct a hood for the halides myself w/ fans etc. The reason for the 2 250's is I could use the later on another tank. What you recommend for my system, I know I should choose the corals before light, but I just want more light as is since my tank it too dimly lit. Though I know the usual rule of thumb is 3-5 watts per gallon would it hurt to have more?  < hi sounds like you have been doing your homework. I would go with the 250 watt halide system with VHO actinics the tank is 24"tall so you would get good penetration to the bottom of the tank. any future tank you do will more than likely be 24" tall to so you can use them on a bigger tank. when you first introduce corals place them near the bottom of the tank and move them up slowly Thanks for the question and good luck MikeH>  Thanks 

Last HQI questions before ordering 10/21/03 I really appreciate you spoon feeding me about lighting but after frying my coral collection with too much light a few years ago, I am scared to death to upgrade my lights.  I've read through all the lighting articles and FAQ's, I have done many google searches for more lighting info, and have visited other online sources and lighting companies.  These are the last few questions I have been unable to find answers for. I've found that an IceCap VHO retro kit with fans is going to be about the same amount of $ as a HQI 150W system.  I am leaning towards a PFO HQI ballast and 10K Ushio double ended bulb from Champion Lighting with a Reef Optix III pendent from Specialty Lights.com (I hope this is not stepping on toes, but I've never ordered from specialtylights.com, do you know if anyone has ever had problems w/them?)   <do keyword search the big message boards for a broad consensus on customer opinion here> Corals grow well under 10K HQIs, but how is their color to the human eye under 10K HQIs?   <very attractive to most people... it is perhaps the most popular lamp color at present> Will they need supplemental actinics to balance out the "look" for the viewer or are HQIs fine as the only light?   <nope> Are the 20K's too blue or are they better for deeper water corals? <both... seriously> Will HQIs over a 50 g 18"H with 2-3" sandbed be too much light for Pectiniid corals? <hard to say... depends on where the specimen was collected. Likely not though> Thank you for all the help you've given me on lighting, this has been a scary thing for me to do what with the bad experience in the past and the output of so much money for a new system.  I am afraid that I will put all this money into something that will only cause more prob.s or after the purchase is done, I'll find out that I should have done it another way.  Your input and experience has not only tempered many of my fears but I never really considered HQIs before Anthony recommended them, thanks so much for "holding my hand". Sincerely, Chris     <wishing you the very best. No worries, the 10K HQIs are excellent all-purpose reef lights. Anthony>

MH Question 10/18/03 Please forgive me if this is a repeat question, I did search, but did not find a similar one posted for my aquarium size.   <no worries... it s a big site. Please revise the following article. It reveals all for over/under 24" vessels and with admonitions to be mindful of picking your inverts before you pick your lights (not just saying "garden reef" with a little of everything... which cannot thrive in the long term for the unnatural mix/compromise of light/water quality etc: http://www.wetwebmedia.com/marlgtganthony.htm > I am setting up a new reef system (36x18x20) with a garden variety of corals and clams.   <please do reconsider this. It is not possible or practical to expect corallimorphs collected as deep as 60-80 feet deep to thrive in an aquarium with clams and stony corals collected in less than 20 feet of water> I am moving from pc lighting to metal halides.  I am pondering the use of two 175 watt 14K lamps or one 250 watt 14k lamp...or would the use of a solo 175watt suffice?   <the 250 is likely too much... and the 175's may be too if you lean towards LPS and softies. Instead, two 100 watt double ended HQI lamps would be excellent. Or take a look at the new T5 fixtures> Also, I am leaning toward Hamilton Technology for the pendant and lamps.  I would appreciate any feedback. Sincerely, Jeff Morgan <pendant halides are not at all recommended for a tank this shallow (poor distribution of light... see my article on Moving Light Systems (MLS) here on WWM which addresses general lamp type/orientation issues. Also, you may want to browse the message boards regarding customer service and feedback for the company you have mentioned and others. Trust me :) Anthony>

Big City Lights - 250 watt MH over 24" tank... chachacha! 10/14/03 Thanks for the input Anthony.  If I decide to go with mostly SPS in this reef (I'm leaning to Acropora, Montipora, Hydnophora species), would your light recommendation still be appropriate?  Or should I bump up to the 250s? Thanks again.  Greg <you can still easily use the 175 watt lamps. In fact, the Montiporas are moderate with some low light species. And the Hydnophora are also moderate light denizens. Some of the Acros are high light indeed and can be kept in the top 12" of the tank nicely. There are lower light acros just the same (bottlebrush varieties... and the spindly/popular A. formosa blue tip). I did get a hint form your prev. message that some narrow-sighted hardcore SPS keeper(s) got to you and convinced you that you needed an arc-welder over your tank... er, I mean... 250-400 watt halides <G>. Only if you will be keeping strict shallow water species like Goniastrea brains, yellow Porites, Yellow Sarcophyton elegans, and the most brightly colored acros would I even consider the higher watt halides. Best regards, Anthony>

-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

-Adding MH to existing PC's- Hello - I could most certainly use your advice on a lighting situation I'm attempting to upgrade. <Will do my best!> I have some live rock and sand, a few fish, and a small bubble tip - (my perculas are in heaven!).  We do hope to be judiciously adding a very few polyps or corals later.  The tank is a 42 gal hex (Oceanic) and things are going pretty well (Bak Pak 2 and lots of additional water circulation)...except we can't seem to find a successful way to get rid of one particularly evasive oenone fulgida... <?!> In any case, we purchased a Coralife Power Quad 96 watt unit (2 10k and 2 actinic), but my wife says "WE STILL NEED MORE LIGHT!"  She says we need to get up into the 4 - 6 watts per gallon range (we're now at about 2.5) to be able to have the most options with possible new polyp and/or coral additions. <The watts per gallon rule is pretty cheesy. I'd go with at least a 175w MH pendant as an upgrade.>  Questions are as follows: Is there a MH solution (say, a reasonably priced, small footprint, 175W pendant) that I could add to my current lighting that you could recommend? <Sure, the most reasonably priced halide fixture would be a hanging bell or horizontal (horizontal is better!) at 175w. My favorite 10k 175w lamp is mfg by Ushio.> As for color temperature, what would you recommend or find pleasing personally to complement what I already have? <10k Ushio> If I must scrap the lighting that I have, what would you do to start over? <You don't need to scrap it, but if having the pendant on along with the PC's it may look kind of sketchy. If this is the case, you can go with a fan cooled hanging pendant with 28 or 32w power compacts along with a halide bulb of your choice.> BTW, because of the hex configuration, a small pendant would most likely work/"fit" well, although there is no room for more PC/fluorescents if we keep the Coralife unit. <You won't need anymore PC's.> Thanks so much for continuing to offer the best advice that is available anywhere!  You guys are "da bomb"... <Thanks, I hope this is of some assistance! -Kevin> - Garland

-Mounting fans in canopy- Dear Crew I just received my MH/PC retrofit. I also bought 2 Ice Cap fans.  My question is this: What is the best way to place them?  One at each end of the fixture? Across from each other?  What? <One on each of the long ends, one blowing in, one blowing out. Good luck with your new lights, and enjoy the new found heat! -Kevin> Marion

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! Have fun, and be safe! Regards, Scott F.>

Metal halides? 09/09/03 <Hi Kevin, PF with you today.> I have a tank that is about 55g and 3ft by 3ft and 1 1/2 ft high I was just wondering what type of light should I use? (I was thinking metal halide) and what degree of Kelvin? How many watts? Do you know where I could get the pendant for cheap? Thanks, Kevin <Well Kevin, what kind of lights you want depend on what kind of animals you are deciding to keep. Will this be tank for primarily soft corals? SPS? LPS? Fish only? Buying lights before planning out the animals is putting the cart before the horse. Also, cheap doesn't necessarily mean good. A cheap pendant may have higher hidden costs, such as power, shorter lamp life (and they're the costly part over the long haul), etc. Lots to think about before you get to the lighting. Let us know, and we'll help you out some more, PF>

-MH lighting on a 3' reef- I have a tank that is about 55g and 3ft by 3ft and 1 1/2 ft high <Cool dimensions! Well, except for being very deep> I was just wondering what type of light should I use? I was thinking metal halide) <You better believe it, 36" is extremely deep. I'd suggest 400w MH> and what degree of Kelvin? <That's your preference. I'd use 10k Ushio if you were supplementing with VHO actinic for a nice ice-white look, 65k Iwasaki for a nice, IMO, true daylight look when combined with VHO actinics. There is also much written about 20k Radiums, but I'd suggest you hit the forums for opinions on those.> and how many watts? <400w, minimum, this tank is really deep. So, now you're probably thinking, how many lamps? Well, so am I! I would think that you'd need at least 2, optimally 4 lamps over this tank for good solid coverage. I would also suggest running 2-4 3' 90w VHO actinics in either set-up for better color.> Do u no were I could get the pendant for cheap. <This will likely be a retro-fit job if you go with 4 lamps. If you go with only 2, you can get a nice fabricated to order hood from either PFO or Hamilton Technology. PFO is sold by most online shops, Hamilton can be bought from some online shops or from them directly. Good luck! -Kevin>                                   Thanks                                          Kevin

Aquarium cross braces I appreciate all your support in the past and am presently trying to solve a problem with my 330g tank. It is 84"x30"x30" and it is 3/4" glass. When the built the tank in my home they put two 1/2" glass 14" cross braces in 14" from each corner. This lead to a 14" opening 28" opening and then a 14" opening. The problem I am having now is the left and right halide is directly over the cross brace. This is dimming the light and I am sure must be changing the spectrum of the bulb. <Agreed> Not to mention also warming the brace itself. My question to you is do you know, or know someone that would be able to help me fix this with problem with smaller braces having to be thicker or some other solution? <Not smaller... but you could cut the current braces and move them to the middle of the tank> I know from what I have read that they should have spaced them out more evenly. This would have helped to some degree but the braces need to be about 8" wide to really help with the lighting. Thanks a lot for your help and have a great day, Ian. <Is it worth considering moving the lights out over the side cut-outs and adding a third (perhaps higher wattage and temperature) MH to the middle area? Bob Fenner>

Re: Aquarium cross braces I am sorry for not giving you the complete information on my lighting. Currently I have 3 175W Halides 10000K and two NO Actinics. I also have a combination of SPS and LPS corals, clam, leathers.  I don't mind your idea of moving the lights around. I could move the two end ones out over the 14" opening. Then I thought I could add another 175W Halide to the middle opening so there would be two. Would this be enough lighting for over my tank or should I consider getting two more halides of higher wattage for over the cross braces. <For this depth (30 total inches if memory serves) I might well increase the wattage of the center MH... perhaps a 250 Watt Pendant... and move your clam, perhaps some SPS there> If so what would you recommend for over my 30" deep tank? Thanks for all your help it is greatly appreciated. <Many possibilities... perhaps review the MH FAQs archived on WWM re others choices in lamps, fixtures. Bob Fenner>

Metal Halide lighting 9/2/03 Thanks for the response.  One more question.  The DE bulbs in 150 and 250 watts. My impression is that they give off more PAR and thus are brighter than the mogul type bulbs.  Is this true and would a 150 DE be comparable to 175 mogul? Thanks, Sam <the point may be altogether moot. Aquarists often get caught up in buying their light systems without considering/knowing their exact species list. Even worse if they want a garden reef mix (unnatural hodgepodge of SPS, LPS, clams, soft corals, etc). It assumes that all such corals have standardized needs for light despite coming from wildly different depths and turbidities. My advice is to make a list of corals first... focus on a niche (shallow water, daylight color like Iwasaki)... deep water as with LPS/corallimorphs (cooler lamp with still high PAR like Radiums)... or run down the middle with Ushio/Aqualines at 10K. Best of luck, 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

Shedding A Little Light On Bulb Choices Hi Crew, <Hi there! Scott F. at your service!> I'm going to be setting up a 150 gallon reef tank in the next few months and am sure to have a few more questions for you between now and then but, for now, I'm wondering what wattage of Metal Halides to use?  My tank dimensions are going to be 48"x24"x30", 30" being the depth and was figuring on using two bulbs equally spaced across the top.  I plan to make this an SPS tank emulating a shallow reef environment and plan to stock accordingly.  Much research left to do on coral species relating to said niche but have found your site to be an invaluable resource.  Keep up the great work!  Also, what would be a good color temp to use here? Regards, Ron <Well, Ron, in a tank of this depth, I'd use nothing less than a pair of 250 watters...I like DE bulbs, but the choice is yours. I am a big fan and recent convert to Aqualine 10000k's, supplemented with some actinic (for aesthetics) if you want some blue. The colors of your corals will be awesome! I used to use exclusively 20000k's, but coral growth didn't seem as significant. My SPS nerd friends would want to frag vital bits off of my favorite body parts if I don't at least mention that you could consider two 400 watters as well. I think that is overkill, myself, but some people feel that you just can't get enough light for SPS...Hope this helps! Regards, Scott F>

Metal Halide lighting Hi Guys, As always thanks for all the work you put into this site! My plumbing is done and here are the specs: 30 g tank (tall), 30 g sump, Aqua C urchin skimmer, Rio 2500 return pump (three and one half one half feet of head), and two powerheads.  Aquascaping will be 3 inches of sand in tank, 6 inches in  sump refugium for planting, 30 lbs of live rock.  Proposed livestock- SPS, clam, some inverts, and 3 fish.  After some research my though is  a pendant MH of 175 or 250 wattage with 10k bulb. Once established (1-2 years) my next tank will be 90 g with inhabitants moving on.  MH would be part of equipment to be used in larger system.  Question is what MH system should I use and bulb choice.  Also, any other recommendations would be greatly appreciated. <All sounds good. I like the looks of the AB 10000K bulb. This can be very subjective to the person though. Try to find some setup in your area that you can look at to find what looks good to your eye. IMO 175 is probably more than you need and you can adjust with height. The 250 is overkill. I would go with < 1" or 6" > in the main tank (probably < 1" for me since you have the sump). Don> Thanks in advance. Sam

MH for a 84x24x24 200 gallon Hello Bob, I have been reading and reading everything I can find on the net, in addition to your book and still I'm confused.  Even some of your advice has me confused.  I'm just trying to figure it all out.  Here you're answering a question about MH: <Okay> "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 folks 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>" Advice given; go with the 250's. Now the exact same question and tank size: "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>" Advice given; go with the smaller 175's. So my question is, should I go with 3x175 or 3x250 or 2x250 and 1x175?  My tank will be stocked with all of the usual SPS, LPS and soft corals.  Thank you for your time. Michael <Sorry for the confusion. In reading, re-reading the above questions I am struck by the difference in the use of the term "few" SPS and Clams in the second and the words "all" the clams and "no problem" in the first... I would still encourage any given reef aquarist with "some" SPS and Tridacnids to settle on the lower wattage (175) lamps for this size, shape system and the larger (250) watt units for "all" the clams and SPS they might desire (along with boosted means of alkaline and biomineral supply). Even larger wattage or more fixtures could be used in maximizing production... with incipient costs of acquisition and use... but at what "other costs" of maintenance, stability? Do understand me here... the 175's will work... the 250's are better for maximizing growth, color... and even 400's might be employed... the lower wattage will provide the best long-term radiation, growth (though not the fastest) and health of livestock (IMO of course). Bob Fenner>

-250w floodlights suitable?- Hi there fellas, I am planning to upgrade to MH on one of my tanks.  In my research, I have run across some 250w MH 'floodlights' that look very similar to the rectangular pendants sold for reef use.  My question is, can I put a 'reef bulb' in this light fixture and save some money? <If it's the correct ballast with a mogul socket you're good for go! Although it seems kind of straight forward, you may want to try firing someone's old 250w MH lamp first, just in case. -Kevin> Thanks a bunch, Aquaholic

Re: Lighting for FOWLR If I went with 3 250W MH will that be too much light for any fish?  Do you recommend one manufacturer of MH bulbs over others (maybe better quality/value/etc.)? <Well, D'Wayne, that will certainly provide ample light for a FOWLR <G>. Should not cause a problem. The Aqualine/Buschke seems to get high marks around here. Don> D'Wayne

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 on Refugium 7/30/03 Dear Anthony, <cheers, my friend> Thanks for your response regarding MH lighting for my refugium. I have not been able to find a 100 watt system with a parabolic reflector and either of the double ended bulb brand names you suggest. I would appreciate your opinion on a system I have found at a reasonable price. <I was thinking more along the lines of a DIY canopy... but if you prefer a finished product, we'll find something..> It is a Sun System Blue Wave 150 watt, 10,000 K, double ended Ushio bulb in a sealed "box" (rectangular, not parabolic) with remote ballast. $395. <a fine choice... and do consider modifying it yourself with a better reflector if the stock one seems mediocre> I am happy to go with 150 instead of 100 watts. <agreed> I just can't find a unit with either of the bulbs that you like and a parabolic fixture. <no worries> Any vendor suggestion would be useful. <again... it was a DIY assumption. My bad :) > As always, my appreciation, <and my kind regards> Howard in Wisconsin <yes... be seeing you and piles of cheese at the Wisconsin reef club 3rd week of September as I recall>

Tank cover - filtering MH? 7/30/03 Hello Anthony! <cheers> My today's question is concerning cover for my tank. My tank is completely opened from top and I have a 250W MH lamp hung 30 cm above the water surface. Today my two sons were playing in the living room and a small ball was dropped into the tank, which leads me to the question: If I place a cover, simple glass or acrylic, leaving empty spaces on left and right side to allow aeration, would it be a problem? <it may affect (sometimes for the better... sometimes for the worse) the coloration of some corals by filtering the light and UV through glass. More importantly however... the lack of a concealing or enclosed canopy (as evidenced by the ball finding its way in freely) gives me great cause for concern regarding the naked MH light being seen by you or your family. Human eyes should not be allowed to look at the MH lamp unprotected... do conceal this better my friend as with a hooded canopy> Would it cut on my lights penetration or have some negative influence on aeration?? <the light yes perhaps... but the aeration is little issue of concern. You can inject enough aeration otherwise with good water flow and protein skimming> I would prefer acrylic cover, because it is light and it is does not break easily. However my concern is that acrylic absorbs some lighting. Your input would be much appreciated. <the acrylic is not without problems of its own (warping and discoloring quickly in time). Perhaps a piece of tempered safety glass would be better. Seek as clear and thin (say 6mm or less)> Thanassis, leaving for 10-day holidays. <safe travel and return my friend! Anthony>

Metal Halide, ballast going bad? 07/29/03 <Hi Chris, PF here today> Dual Ballast 175 watt  Metal Halide is what I have. I bought it used but I think it is made by PFO. My question is: I am getting ready to set up my new aquarium and was checking all of my stuff for it. I was checking my lights and the one of the lights works perfectly, and the other lights up and as soon as it starts to get really bright it flickers and shuts off. What would be causing this? Is the ballast going bad or the capacitor? I thought Anthony may have know something about this. He has answers for everything, I'm very glad he is a part of the WWM crew! All of you guys there have been wonderful in helping tons of people. The ballast are made by Venture Lighting I have sent two email and have not received a reply yet. The bulbs are not bad, just will not stay on. I am thinking it is the ballast but I am not sure. Is there a way that you guys know of that you can test out to see what is going bad? Please let me know what you think, I really appreciate all of your help! Thanks, Chris Hepburn <Well Chris, it does sound like the ballast to me. Have you tried contacting PFO directly? I had trouble with mine and they were a big help. You might want to check their website and see if they have a number to call. Sorry I can't be more direct, but electronics aren't my specialty. I assume you tried both bulbs in both sockets? You could also try an electronics repair shop, if your efforts with the manufacturer don't pan out. Good luck! PF>

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 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>

MH lamp orientation/color II 7/19/03 ...and also for my set up.. its time for me to replace my MH bulbs I was thinking of having 6500k instead of the 10k... do to the fact that my LFS is telling me that clam and SPS corals grow best under those lamps instead of the 10k and also would the 96x2 50/50 power compacts balance that light as it has more yellow content in it. <I would agree that 6500K lamps are very good for zooxanthellate reef creatures. Many good lamps out there. Iwasakis 6500K are very fine. Anthony>

MH lamp orientation III 7/19/03 thanks for your prompt response, I will certainly digest that information... one more question... just to be sure I understand, there is really nothing bad about having the pendants, just that they do not disperse light as wide... <essentially true... pendants are best for tall narrow tanks> so for my set up which is 48"x18"x20" is true that a pendant is good for about 2' of tank length and depth and if that is the case then my set up is just fine or is it something that needs to be corrected? <it is not so much "good", per se, for 4 foot long tank but instead has a rather narrow and focused beam of light to deliver. 3 vertical pendants are needed on a 4 foot tank that would otherwise require only 2 horizontal lamps. Anthony> MH lamps 7/9/03 Anthony,   You won't remember me, but to refresh your memory, I have a 75g reef tank with (as you recommended) dual 175w MHs.  Everything looks great, but now I'm wondering about the bulbs I have.  As expected, the canopy came with Venture 5,500k bulbs, and they're quite white, and fairly generic.  Now, here's the thing: because the canopy is so large, I have no room for actinics.  Is this going to pose a health problem for my coral? <good heavens no... most all MH lamps out there have more blue than corals need in them. The lamps over 10K are somewhat of a waste in that regard> Also, what bulb upgrade would you recommend for coral growth/health?  I have been looking at the 10,000k Aqualine, 10,000k Ushio, and 20,000k XM bulb from hellolights.com.   <I have experience and respect for the first two listed> To be honest, I'm hearing great things about the XM bulb.  What are your thoughts?   <don't believe everything you hear ;) Or rather... ABs and Ushios are time tested and reliable. Getting my vote in preference> Thanks a lot--I'm really hung up on this whole bulb dilemma. Sam Minneapolis, MN <best regards, my friend. Anthony>

New Book and MH Lighting - 7/7/03 I received the new book the other day and may I say what a wonderful book it is!!! I have learned a lot from it and I have only scoured the first few chapters!!! Can't wait for the next in the series!!! <Thanks for the inspiration <G>!> I currently have an AGA 65 gallon, and have changed (this past weekend) to metal halide lighting. I have a PFO 175w ballast running a AB 10K bulb. I'm not real pleased with the color (kinda yellow) and it's not real bright. Any suggestions? I was thinking about switching bulbs to the Ushio or Blueline 10k bulb. I'm looking for a bright, crisp white color. <The Ushio is a great bulb IMO... but the Blueline I would not personally take for free. Your AB is also a fine quality, if not color, for cnidarians> Again, great book!!!! Thanks, Jim <Much appreciation my friend. Best regards, Anthony>

The "XDE Factor" Hello there. <Hi there! Scott F. with you today!> I was wondering if you Guys got any good dirt on the [XDE 250W 20,000K double ended] HQI form Hellolights. Is it good light? Will the bulb last and burn ok, will it work ok with Hamilton HQI ballast ? Any charts on this light? I can find any. <I don't know about the bulb's compatibility with the Hamilton ballast. You may want to talk to the helpful folks at hellolights.com on that one. I can say that I have seen the bulb in action, and have heard positive feedback from users. It looks to be a bit less "blue" to me than the Radium or Ushio 20,000k's. My friends who have tried them like them and claim good results, although I have not seen any tests or PAR information on them (I'm sure Sanjay Joshi will get around to it soon, though!).   Trying to bring the colors back in my tank the one 250watt MH 10,000k Hamilton bulb is to white and yellowish to me. <I agree with you about the appearance of most 10000k's. I use Aqualine 10000ks right now, and find them to be too "yellow" for my aesthetic preferences...I like Blue!> I liked the VHOs looks two white two blues on my 180 reef. <Yep- a more "balanced" look, IMO Trying to find someone that has used this light and what they thought of it. Thanks for your time. <Do ask around on the WWM Forum, and see if any of your fellow hobbyists have had experience with the bulbs, or can send you som pics...Good luck- and send pics of your tank should you go the XDE route! Regards, Scott F.> Chris

- 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

Question on metal halide lighting 6/29/03 Hi have you heard of Sunsytems? <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>

Salt water change- metal halide lighting 6/28/03 To Anthony Calfo-in Alf Nilsen new book wrote that if you have a balance reef tank you do not need to do water changes. <I sincerely admire Alf Nilsen, and would feel better to read the statement in the context in which it was said (I would be surprised if this was a recommendation... but rather a concession under rare circumstances)... but at face value I would disagree. It presumes we know how to export every deleterious element, and how to import every necessary one in balance> On Dr Mac web site said that if you SPS corals you will need 400 watt metal halide lighting for a reef tank like this. <for aquaria deeper than 24" and with shallow water SPS coral species placed throughout the range, it may be true/helpful> I would like to know your thoughts on these two statements. You must happy that book as finish. <very, very happy my friend! I'm in sunny SD as we speak... finished breakfast with Bobster and will get back to signing the pre-order books for posting first thing Monday morning <G>> as always    RGibson <kind regards, my friend. Anthony>

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

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>

20K is Ok! Good morning. <Hey there! Scott F. with you today!> My question for today: I am thinking about ordering retrofit kit with MH  2- 250 watt 20000k bulbs. I was told that I could only leave the lights on for 6 hours a day and not 12 hours because of a potential algae bloom. Is this true? The tank is 120 gallon. Thank you. Cecilia <Well, Cecilia- the light spectrum really is not the cause of nuisance algae. It's more of a function of nutrients which favor algae growth, in combination with high light intensity. For example, there are numerous hobbyists working in the field of coral propagation, and they are often growing corals out in greenhouses, with abundant sunlight. With proper husbandry techniques, you never hear of algae problems in these systems. I think that you'll be happy with the results of the 20000k bulbs, when used with animals that utilize this spectrum, and with common-sense nutrient export mechanisms. And the photoperiod? Use what works for the animals you keep! Good luck! Regards, Scott F>

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