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FAQs about Metal Halide & Halogen Lights and Lighting for 40-200 Gallon Marine Systems 1

Related FAQs: Metal Halides for Medium-Sized Systems 2, Large System Lighting, & Metal Halides for Medium-Sized Systems 3, Metal Halides 1, Metal Halides 2, Metal Halides 3, Metal Halides 4, Metal Halides 5, Metal Halides 6, Metal Halides 7, Metal Halides for Small 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,

Small Marine Aquariums
Book 2: Invertebrates, Algae
New Print and eBook on Amazon:
by Robert (Bob) Fenner
Small Marine Aquariums
ook 2: Fishes
New Print and eBook on Amazon: by Robert (Bob) Fenner
Small Marine Aquariums Book 3: Systems
New Print and eBook on Amazon:
by Robert (Bob) Fenner

175Watt vs. 250Watt/Reef Lighting 10/25/09
<Good morning, Jeff>
I really appreciate all the great advice you provide. It has been very helpful.
<You're welcome.>
I now need some help on which metal halide would be the best for my new 120 gallon (48x24x24) reef tank. My plan is to use (2) XM 250W 10K SE or (2) XM 175W 10K SE metal halide bulbs within (2) LumenMax Elite reflectors.
I also plan to use a Galaxy Electronic Ballast.
Sanjay Joshi tested both bulbs with the Galaxy ballast with the following results: the 250 watt had a PPFD of 133.2 and a CCT of 9860, the 175 watt tested at 80.4 for the PPFD and 10514 for the CCT. The PPFD for both bulbs will no doubt be higher within the LumenMax Elite reflectors.
<Should be, and for other readers sake, the acronym PPFD (PAR/PUR) means photosynthetically available/useable radiation, or the intensity of the bulb between 400nm and 700nm, which is what our corals use. The CCT is the actual corrected color temperature.>
The corals I plan to keep are SPSs, such as Montiporas and Acroporas. I also plan to keep LPSs such as Euphyllia divisa, E. ancora, E. glabrescens and my personal favorite Plerogyra sinuosa. I may also keep a xenia, some Zoanthids and perhaps a gorgonian.
My concern is if I go with the 250 watt bulb would it be too much light for the LPSs?
<No, not at 4 watts per gallon and a 24" deep tank.>
Would the 175 watt bulb be enough light for the SPSs?
<Should be enough with a 48" long tank using 10K lamps. I run two Ice Cap 175 watt 10K's in a 60" long, 18" deep tank and is providing good SPS growth.>
I have always thought I would go with the 250 watt but the more I read about the LumenMax Elites the more I am worried that it may give too much light for the LPSs. If this too much light would the 175 watt bulbs be enough? What is your opinion?
<I'd go with the 10K 175's if it were mine. If you decided to run 14K lamps or higher, go with the 250's.>
If I may, an off the topic question, what are the two best "reef safe" centroyge <Centropyge> angelfishes?
<In my experience, I've always had the best luck with the Coral Beauty, and/or False Lemon Peel. Both have been well behaved in my system going on three years now.
Is no guarantee, with caution is always advised with Centropyge.>
Thanks again for the help.
<You're welcome. James (Salty Dog)>
Re 175Watt vs. 250Watt/Reef Lighting 10/26/09

Thank you for the quick reply.
<You're welcome.>
I think I need to mention that I also plan to use (2) actinic T5s to go <with> the metal halides.
Does that change your recommendation?
<No, will just add more light in the 460nm range. Many folks will do this when using 10K lamps.>
thank you.
<You're welcome. James (Salty Dog)>
Re 175Watt vs. 250Watt/Reef Lighting 10/26/09

I am thinking I will follow your recommendation and go with the 175 watt metal halide but like to know what advantage do you see it having over the 250 watt. I know it would be less expensive to operate and perhaps less heat, are there any other advantages?
<No other advantages other than what you mention above. For your size system, the twin 175 watt, 10K's will be fine. Do read the entire thread again, and you may want to read here. http://www.wetwebmedia.com/marlgtganthony.htm
Thanks again.
<You're welcome. James (Salty Dog)>

Metal Halide Question 3/31/09
A question I can't seem to find a clear answer on. Currently I have a 100g, 72x15x20 with 2 250w MH and 2 175w MH 10k Coralife bulbs and 2 48" super actinic T5 HO about 12 inches above the water. Everything is doing fine and my clams are in heaven but my sps seem to be out growing the width of my tank quickly. I'm moving in 2 weeks and picked up a new tank 60x18x24. I would like to use the 2, 250w MH and the 2 actinics on the new tank and move everything over. Will this be good enough for a mixed tank, will I get enough coverage with this setup. I could use the 175w MH also but really don't want to overkill or pay the high PG&E in my new house.
<I have a 60x18x18 tank that is lit solely with two 175 watt, 14K halides. I have both LPS and SPS corals that are growing very well. I also have a Tridacna crocea clam that is also doing quite well and showing signs of growth. With your added 6 inches of water depth, I'd go with the two, 250 watt halides. The actinics would be an aesthetic option for you but would not be necessary.
James (Salty Dog)>

70g - which light set-up metal halide fixture 2/20/09 Hello, This website is fabulous. <Thank you and hello Monika.> I've come across your website about a week ago - since, I've had no sleep because I've been searching the forum 24 hours a day!! <Some of us that answer queries here are equally obsessed with the site!> I've read the information about lighting over and over and still am quite confused which light set-up is best for my tank. <Okay.> I have a reef tank - 70 gallon (36"l,18.5"w,25"h) w/o canopy, 130lbs live rock, AquaC Remora, water parameters with in normal limits, and currently running 3x96w 50/50 compacts. Reef inhabitants include a maroon clown (going on 10yrs), PJ cardinal (going on 7yrs) and 3 baby chromis, shrimp, sandsifter and cleaner crew. Corals include a pagoda, torch, leather toadstool and finger leather, xenia, variety Zoas and mushrooms and a plate coral. Everything is thriving and doing well. These lights have worked but I would like to upgrade. I most likely (at least not in this tank) not house sps corals. <Good, it sounds like quite the mix already.> I really enjoy LPS, soft coral and polyps and would like more. Here are my current choices: 1) SunPod 2x150w HQI metal halide (comes with 14k bulb...would it be better with 10k) <If you are going to run a single bulb on this tank the 10K would be a better option here.> 2) SunPod 2x250w HQI metal halide (thought this may be too much) <Yes too much for what you are keeping.> 3) outer orbit 1x150w HQI 2x96w (not sure what kind of bulb to run...I like the blue look from my actinics in current setup) I was initially going to go with the outer orbit. I've since changed to SunPod 2x150w since I've heard so much success with using metal halides, that the corals will thrive and grow well and that I will really like the color from these lights. <The 2X150 is a good choice, but the question must be asked. If everything is doing so well, why change? What is your current lighting?> Any help would be greatly appreciated - I'm so confused!!! Thank you for taking the time to educate us :) Monika <Welcome, Scott V.>

Re: 70g - which light set-up metal halide fixture    2/22/09 Thank you for replying. <Welcome.> I apologize for the lack of information. I am currently running 3x96watt 50/50 power compacts. Why I want to change lights: These are Coralife fixtures (one is a single pc and the other is a double). They are roughly five yrs old. They have worked well but are showing there age and one of the fans have been making an odd noise this last week. Also, I absolutely hate the legs on the fixtures and don't care to have two fixtures....so I've been looking for something new :) In the previous email, you mentioned that 2 150w HQI MH would be a good option. They come with 14k bulbs. Should I use 10k bulbs for both MH? <If you like, but on a 36" tank the light from these bulbs will overlap somewhat, so 14K is a fine choice if you like the look.> Will I get the aesthetic look that I currently get from my pc's? <It will likely differ, hard to say. Even not all 14K HQI bulbs look the same.> Also, you asked if I was going to run a single bulb - do you mean a single fluorescent - an addition to the metal halides (I'm sorry, but I don't understand). <No, I was referring to the halide. On 36" long tanks some do use a single MH bulb, with the ends of the tank being a bit darker.> I guess I'm wondering, if I do go with 2 MH - is that all I need for what I'm trying to achieve. <I do believe so....if you go with the 14K you will not need actinics to blue it up, unless you like an extremely blue tank.> Thank you kindly for all your help, Monika. <Very welcome. Do keep in mind through all of this the extra heat the MH will add to your tank. Scott V.>

Re: Hole Size - Approximate - theoretical Maximum Flow 1/18/09 I'm filling the tank!!! I cant believe it!!!. Finally!!. I tell you if I never walk into a Lowes again for the rest of my life it will be to soon!!! <I hear you, congrats!> So quick tid bit of information I just learned. I was pleasantly surprised (actually quite pleasantly) to find that when I unpacked the Outer Orbit fixture I purchased from a gentleman on craigslist as a "48" roughly 560W fixture (2 x 150 MH-HQI, 4X 54W T5, 18 Lunar lights) is actually 48" 729W Fixture (2 x 250 MH-HQI, 4 x 54 T5, 18 Lunar) !! I cant even believe it!! But anyway the question that pops into my head now is. You mentioned early on that given my tank dimension (48W X 24D x 30H, taller than normal) the pair of 150's would be borderline insufficient. I was looking up the possibilities of a 250 upgrade when I took a closer look at the unit and noticed that the info I assumed was wrong and that this unit is the higher wattage one. Given this new bit of info, how do you think I stand in the lighting department? Feed back? <Looking good, 250s are the way to go here.> Concerns? Should I put stuff closer to the bottom , step the light intensity so nothing gets burned? <You will want to be sure to acclimate anything you put in the tank to the lighting depending on the lighting on their previous system. See: http://www.wetwebmedia.com/acclimcoralslight.htm.> Just want to make sure I don't bake anything and that I get the most out of this most fortunate twist of fate. As always thanks for sharing your knowledge and advice. It makes the experience some much o Joey Freyre <Happy to help, have fun. Scott V.>

250w halide Reef Lighting/Selection 1/18/09 Hi, <Hello> I just wanted to make sure I have the correct wattage halide for my reef tank. I don't have any stony corals, only softs and 1 anemone (along with some fish) in a 54 gallon old-style corner tank (3 front glass panels and 2 back ones in a "V" formation). The tank is 25" tall and I was told by a number of people to get a 250w halide to keep everyone happy all the way to the bottom. Can you confirm this for me? <If adding SPS corals is in your future plans, the 250 watt halide will handle their lighting needs just fine. Reading here will further benefit you in your lighting selection. http://www.wetwebmedia.com/marlgtganthony.htm> Thanks. <You're welcome. James (Salty Dog)>

Lighting 200 gal reef 12/16/08 Thanks for doing an excellent job. <Thank you for reading, writing.> I have a choice of two light fixtures for a 200 gal. tank which measures L72" X W24" X H30". They both have four PC's which I believe are 96watts each, but the choice is the three metal halides, either 150 watts, or 250. Which would you recommend? I currently have 6 X 96 watt PC's and want the metal halides. <If you intend on keeping the same livestock you have with your PC's the 150s can do, but for a 30" deep tank 250 MH bulbs are the way to go. It will give you the flexibility of keeping just about anything lighting wise within the tank. Light intensive livestock in the upper half, with less needy inverts down towards the bottom. With 150s you will be a bit more limited, keeping things such as SPS in the upper third or so.> James Wedel <Scott V.>

MH HQI replacing PC's? And Cnid. incomp. non-action  -- 10/02/08 Hello there! I have a real quick question on lighting that's pretty unique, hoping for your suggestions. It's that time again to change my MH HQI lamps and PC's (been 12 months). Currently the set up is two HQI 150 watts and two 96 PC actinics (Aqualight Pro) on a 90 gallon (48 x 18 x 24) that have recently been converted to a predominantly SPS tank mixed in with some LPS's. SPS's are in the middle to upper half of the tank and LPS dominates the lower portion of the tank with many Acans and Blastos. Now to my question, I have began noticing 70 watt HQI's in the market recently and I am wondering if I could replace my PC's with those to be used for supplemental lighting, I'd probably use a 20,000K bulb. Well first off, is my current set up sufficient for SPS corals? <Mmm... IF these were "elevated", placed "higher up" closer to the lights... likely perched on rocks or such, yes> Second, I think a 70 watt MH HQI will penetrate much deeper than a 96 watt actinic PC <Mmm, am not such a fan of actinics period... they don't do much functionally. Read here: http://wetwebmedia.com/marine/setup/lighting/actinicfaqs.htm> plus I save some money on the monthly electricity bills! What do you think? Would this be a realistic option, using a 70 watt 20,000K as SUPPLEMENTAL lighting? <Mmm, yes, or even principal...> Oh and one more, sorry, I know I said one quick question! My Micromussa accidentally came in contact with my Torch Coral recently (thanks to a very mobile Fighting Conch), and most of it has disintegrated within 8 hours. I checked it the morning and they were fine until I came home from work. There are maybe one or two heads they weren't affected, should I cut them off from the disintegrated meat or just leave it alone? <I'd leave as is (though re-separated of course),... it may well be that the "empty", "melted-off" heads will be repopulated in time> Thank you for any assistance you can provide! Jay <Welcome Jay. Bob Fenner>
Re: MH HQI replacing PC's? -- 10/02/08
Thanks for the quick reply! <... welcome> So would just the two HQI 150 watt 10,000K be sufficient for the SPS (perched on rocks from one foot below surface to near surface)? <Mmm, yes> My plan is to create a dusk to dawn effect by turning on the two 96 watt actinics and then turning then off when the MH come on. then midway through the day have another two 70 watt MH come on. What do you think? Is this light sufficient? <... Is, in terms of photonic strength> Thanks again! <Welcome. Bob Fenner>

Conflicted over MH for Reef 7/3/08 Hey folks, <Hello David.> As the subject line alludes, I am conflicted about whether to upgrade my current lightning scheme (260 watt PC) to a MH fixture. I have an 80 gal with 90 lbs. live rock, one C. cyanea damsel, one Gramma loreto, one tiger pistol shrimp, one A. randalli goby living with the shrimp, one C. strigosus tang, and one Dascyllus trimaculatus. The system has been running for two years. It is a work in progress and has always been intended as a reef tank. I am now at the point where I am ready to add some photosynthetic inverts. <An eventual progression!> I am not really interested in, at this time, SPS type corals, quite frankly because they scare me. <In time they will not.> I have seen so many dying specimens and skeletons in tanks all over the place that I don't want to contribute to the carnage. <Start with frags when the time comes, they grow surprisingly fast.> It could be that I just don't understand them well enough or am unwilling to commit to their more demanding upkeep, but for now I would rather leave them to the experts. I like (and am much more confident in my ability to make happy) most of the soft corals, including mushrooms, xenia type, brain etc. but have always desired to keep a Tridacna clam. I understand from researching your site (Laurie Smith article) that certain Tridacna clams can be kept under PC light in shallow tanks. <Indeed they can.> The water is approx. 20 inches deep from the top of the aragonite substrate to the surface. Is my tank too deep for just PC and a clam? <Not with correct intensity, spectrum and placement.> Would a fixture consisting of two 150 watt MH bulbs mounted 4" above the tank allow me to keep softies low in the tank/substrate while keeping a clam higher up on the rock? <Yes.> Another option would be two 250 watt MH's hung about a foot above the tank or more depending on your recommendation. (These are the fixtures I have thus far found to be in my price range.) <Given what you are inclined to keep, the 150's will do fine with the placement you mentioned above depending on the clam.> Are these two types of invert life (softies/clams) mutually exclusive? <No.> I would be happy with ether one of these MH fixtures, or with just keeping the 260 watt PC's as long as the livestock would also be happy with them, which is my greatest concern. <You could get a lower lighting needing clam such as a Squamosa with this lighting, although any of the Tridacna will be better suited for higher intensity lighting, more PCs or the leap to the MH.> I really want a clam. So, if I must forgo the lower light loving softies in order to keep a clam I will have to think and do some more studying to see what else can be kept with clams that I feel confident keeping, but there it is. <I understand, if you asked me to pick one thing to keep, clams it would be!> I really appreciate this site and the view towards the responsible upkeep of marine life. <Thank you, it is very much a pleasure to be part of.> I hate it when I lose a freshwater fish/invert, which I am happy to say is rare, but I am especially sensitive with regards to marine life, most of which cannot be mass produced in a breeders tank. <Many cannot, but more and more corals/fish are now captive propagated or bred.> Thanks so much for your help guys, David <Welcome, have fun, Scott V.>

Lighting... 75 reef...  03/09/2008 Hi crew, <<Hello Ron, Andrew today>> my question is about getting the most bang for my buck when it comes to lighting. My tank is a 75 gallon ,with protein skimmer, refugium, and live rock. The fish that occupy the tank are a potters angel, leopard wrasse, yellow tang, two percula clowns, and two Bubbletip anemones that have divided several times. My current lighting is a four bulb t5 system. I was considering increasing the light for the anemones, and would like know if it would be a good idea to go with metal halide lights or a six bulb t5 lighting system some of my concern is overheating. Thanks Ron <<The answer, in my opinion, would be to upgrade to either 150w or even 250w metal halide unit. This will remove near enough all limitations on stocking capabilities. Heat wise, a simple clip on fan from a DIY store would suffice, blowing across the water surface.>> <<Hope this helps. A Nixon>>

Halide lighting 150 or 250 More Light Conversation (Lighting Decisions)   2/27/08 Hi Crew, <Hey there! Scott F. in today!> I am privileged to have a few of my questions answered before and have now managed to fill my 150 gal tank (soon to be garden / mixed invert / fish / soft coral). My tank has been running 6 weeks (though half the live rock and existing live stock have been migrated from a 2year old setup) Tank Cleair 6' long, 2.5'' tall,20" deep bow fronted. Drilled at 1.5" with weir. 6" DSB, 120lb live rock, Tunze 9010 skimmer, temp 27 nitrate, nitrite and ammonia all 0, PH 8.2 Lights 4 x T8. Bob has previously advised me that even with the intention of moving to T5 this would not be enough in a 2.5' deep tank. In reality with the DSB this is now 2' <I agree with Bob on this one. Although I use and endorse T5 lighting, in a system of this depth, I think that you'd need to use more of 'em to make this work.> My Xenia which used to look real healthy first took on a quick growth spurt (maybe all that new salt water ?) but now look a little thin and gray (and bunch/curl up a lot more like when the lights are off). Also the green algae (which I did crop back) but which used to grow out of control on my old system (60 gal 4x2x2 with 4 t5's ) is not looking happy. I have had the usual brown, just turning to pink / light red diatom problem which just seems to be subsiding. I have pretty much decided to take the plunge and invest in some MH for the tank in order to give myself the lighting I need now and more importantly when I start adding easy to keep and probably soft corals (possibly an anemone for my clown ?). All 6' light units seem to come in triple units, should I get 150W or 250W units. Everything I have read seems to indicate that 150W is more than enough but I would rather ask and be sure than turn round in 12months and find an upgrade is required. I have read a lot of articles on acclimatization so am happy on the introduction of this unit but am unsure if the sudden new light intensity will spur a problem algae growth. As always thanks for your invaluable assistance. Regards Steve H <Well Steve, first off, let me alleviate your fears about the metal halide lighting causing algae issues. The more intense lighting, in and of itself, will not cause algae problems. Excessive nutrients, in conjunction with light, will cause problems. Continue to maintain excellent water quality, and there should be no nuisance algae growth after adding the new lights. If it were me, I'd opt for 250 lights, even though I feel that 150 watt bulbs can do the job. The main reason is that this will provide you with flexibility if your interests should change to more light-demanding animals. And you don't need to get a multiple light fixture, BTW. There are many fine pendants made by manufacturers such as Sunlight Supply, PFO, Corallife, etc. You can mount them where needed for aesthetic affect, and experiment with placement. Good luck to you! Regards, Scott F.>

Reef Lighting, metal halide and livestock requirements  2/19/08 Hi, <Hi Jay> Great website and I have enjoyed researching on it. <Thank you.> I have a quick question on a newly acquired system that I got from a friend of mine that was moving. It is a standard 75g, 48Lx18Wx20H. It has a dual Hamilton ReefStar unit with two 150w HQI DE 14K bulbs in a wood canopy (2 fans, one pulling and one pushing). The protective glass under the bulbs is about 10" from the waters surface. It also has a retro unit consisting of 2-96w PC bulbs mounted in the top of the hood, but they are about 12" from the surface, hence I'm thinking the PC's are not going to be much benefit being so far up. <Not too much with a 20" deep tank. Can you lower the hood anyway?> My question is on livestock with the dual 150w HQI's: Would a couple of blue/green Crocea Clams/ Blue Maximas and a few SPS do well in the middle to upper part of this tank? I also plan on having some Zoanthids, Ricordea, and LPS like Frogspawn, Hammer, and Acans. It would be a slightly mixed reef, with less emphasis on the clams and SPS, maybe 1-2 clams and 5-8 SPS. Thanks for your great work and help. <Clams seem to prefer being on the bottom, preferably on a sandy substrate. In this regard, considering the depth of your tank and lighting placement, I'd go with either Derasa or Squamosa Clams which do not require the lighting intensity that the Maximas do. Any SPS should be kept in the upper third of the tank. Read here for more info on clams. http://www.wetwebmedia.com/ca/cav1i3/Clam_care/Clam_care.htm James (Salty Dog)> Jay

PC to Halide Upgrade 2/9/08 Hi Guys, <Hello Carl.> I love your site. It's very useful for my job as well as for my personal tank! <Great! Thank you.> I have a huge problem on my hands and need some guidance and fast! I currently have a 46 gallon bowfront with a 29 gallon refugium that I have built up of the past 3.5 years. I have a combination of mushrooms, zoos, Xenia, LPSs, and lower light requiring (Montipora, Seriatopora, Pavona) sps species under 2 96 watt compact fluorescents. Well the one bulb has occasionally been flickering and now one of the ballasts has finally bit the dust (I'm kind of ticked since the fixture is only about 14 months old). <Not good.> So now I only have 96 watts on the system. I thought about just getting a new ballast but have been wanting to upgrade the lighting for some time so I could get more sps. <It sounds like a fine time to do so.> I really like compact fluorescents. Despite what some people say, I really see great growth of my sps under them (although they are in the top 1/4 of the tank), <PC bulbs can support more livestock than people think, I use them on my frag tank.> so ultimately I would love to find a fixture that is a 3x 96 watt compact fluorescent fixture...but don't think this exists (If you know of one, that would be great...). <I don't, outside of using retrofits.> 4x 96 watts I think is too much and I don't have the time to deal with retrofit kits. <I think 4X96 would work fine, you could run the extra bulb as an actinic, for a bluer look.> So currently I am looking at 2 fixtures. They are the 36 in. outer orbit HQI/ PC with one 150 watt 10000K MH and 2 96 watt actinic PC, and the 36 inch SunPod MH fixture with 2 150 watt 14000K MH. I would much prefer the outer orbit for several reasons. It would be easier to acclimate my tank to this fixture. It has PCs and a 10000K instead of 14000K. <I agree on both points.> The downsides to this fixture are that it is wider than the sides of my tank so it would hang over in some spots (not too big of a deal) and the MH is right in the middle and my tank has a 2 inch divider in the middle. Would this block a lot of the direct light if it was around 14 inches off the tank? <I think enough light would get by the brace for your corals, but there will be an unsightly shadow from the brace; not optimal use of the light.> I could replace the 14000K in the SunPod with 10000K but without supplemental lighting I don't think I would like the yellow effect plus that wouldn't be cheap. <No, it would not be cheap to buy the fixture and new bulbs for it at the same time. However, I do think that the 14K will be sufficient here, especially when you consider you will have two bulbs that will overlap somewhat. Also consider the extra heat in your system by switching to halides.> I think another fixture (that I can't find to exist) that would be nice is something with 2 70 watt MH and 1 96 watt actinic PC, however I can't find this. <I have never seen one either.> If I went with the SunPod, do you think that 14000K are still good or is there a big difference in sps growth between the two bulbs. <There will be a difference in the bulbs and how your corals are affected, but I think the dual 14K bulbs are a fine choice in your case.> As I said, I need to make a fast decision so any help would be excellent. Thanks, Carl <Welcome, I hope this helps you decide, Scott V.>

Saltwater Aquarium Lighting, HQI choices, 72 gal.s  1/25/08 Please help and keep in mind I am a girl without a lot of knowledge here. <How about a person gaining knowledge?> We have a saltwater aquarium (fish only) plan to also soon include some corals so we need to change the lighting system. I have decided on the retrofit AquaLight pro HQI, as it has a wood canopy. I believe the tank to be 72 gallons but a tall deep tank. 35" wide - 30" tall - 15" deep. So my question - Is the 150 HQI enough to reach the bottom or should I go with the 250 HQI? <Always depends on what you want to keep and where you want to keep it, but the 250W will give you sufficient light to keep what you want and the less light hungry corals can go closer to the bottom.> I am also concerned about the heat factor but we already have a cooling system on the tank. <A chiller? A 250 will raise the temp some, but if you have a descent chiller I would not worry. Also, fans blowing over the water surface/light can go a long ways towards combating this.> As far as the AquaLight pro everything I have read it seems like a great light system, do you agree? <Yes, it is a good system.> Thanks for your help !!! Crystal <Welcome, have fun, Scott V.>

Lighting 54 gal Corner 12/3/07 I have a 54 gallon corner tank (reef) with a water depth of 21". I want to add some clams. I saw a Current SunPod to fit the tank & can get either 150 or 250 watt MH. Is the 150 strong enough or do I need the 250? <The 150 will work fine, preferably in a 'warmer' spectrum, such as a 10K over a 20K. For a corner tank you may want to consider the 250. This will allow you to raise the lighting fixture a little higher to get a greater light spread without losing the needed intensity.> Thanks. Mitch <Welcome, have fun, Scott V.>

Optimum MH Lighting Color? -- 10/22/07 Dear Crew, <<Hello Russell>> I have a two year old 75 gal tank with 2 X 250watt MH 20K lights (15 inches off the surface) stocked with a half dozen Acro corals and a Crocea clam (also have a pair of clowns, some zoo's, a shrimp and the usual cleaning critters). <<Okay>> My system was originally stocked with softies but I've totally switched over to hard corals. Water parameters are stable with my Geo calcium reactor (Ca=400, dKH=11.2, Nitrate=not detected). I do a RO/DI 10 gal water change with Red Sea salt about 3 times a month. There's ample water flow from multiple powerheads (about 700 gal per hour). I am looking to optimize my system to promote hard coral and clam growth. My LFS (who sold me the 20K light bulbs) says they will work great for my sps corals and I've seen slow to modest growth over a few months. <<Not surprising...too much blue/not enough 'useable' wavelength, in my opinion. 6500K lamps would optimize growth potential...but 10000K lamps are a good alternative that will likely be more aesthetically pleasing to your eye (will also likely have a higher PAR rating than the 20000K lamps)>> I don't have a light meter, but I suspect the cheap, generic Chinese-made lamps I was sold are not true 20K's; they just don't seem blue enough (I would guess somewhere in the 16K plus range). <<This would actually be better...but I suspect these cheap lamps are lacking elsewhere (PAR/CRI)>> Question: Since these hard corals and clams are shallow water animals, would not they be better off with 10K bulbs? <<Not all 'hard' corals have high light requirements...but yes, the stock you listed would do better under 10K lighting, in my opinion>> Or even 6K <<Yes>> (assuming I could stand the yellow glare)? <<Indeed>> I like the look of my pseudo-20K's, but I'd switch if it was worth it. <<As long as your corals are not malaffected by the bulbs you have now...determining the 'worth' is up to you>> Question: Do I have TOO MUCH light (6.6 watts per gallon)? <<Probably more than 'needed' on this tank, but can be managed. Do be cautious about acclimating your tank to the new brighter bulbs if you decide to make the switch>> I know my strongly lit MH's are harsh on my coralline algae growth, which is only growing in the deep rock shadows and almost none on the glass. <<This is typical>> One last question: I'm thinking about adding three blue Chromis fish to the pair of clowns I already have; do you think this would be too much of a bio load for a SPS system of my size? <<Should be fine...and as sparsely stocked (fish-wise) as your tank is, the additional Nitrogen/fish waste will probably be much appreciated by your corals>> Thanks, Russell <<Happy to assist. EricR>>

Re: Optimum MH Lighting Color? -- 10/22/07 Dear Eric, <<Hey Russell!>> Thanks for the fast response. <<Quite welcome>> You've convinced me it is time to switch to 10K lights. <<About the best 'all-round' color temperature>> My coral growth has been okay, but the blue lights are likely a limiting factor. <<Quite possibly>>>> You mentioned "acclimating" my tank to the brighter bulbs. <<Yes... When replacing lamps, and especially when changing to lamps with a lower Kelvin temperature/higher PAR value, you need to take action to prevent photo-shock of your corals before they have time to acclimate/adjust pigmentation to the increased light intensity>> How do I do this? <<Several layers of fiberglass window screen laid over a piece of plastic 'eggcrate' material on top of the tank will work nicely. Three or four layers, removing a layer every three or four days, should do nicely>> I assume by placing the lights further off the surface of the tank (currently about 15 inches... maybe go to 24 and then lower down over time)? <<Can do this as an alternative method...but raising the lights too high puts you/your family's eyes in jeopardy of looking in to the elevated fixtures>> Also, can you recommend some brands of MH light bulbs? <<Ushio and Aqualine-Buschke are my current faves..Hamilton has been a good performer for me as well>> Are the expensive German bulbs worth the price? <<They have proven so for me...seem more durable/less prone to premature failure, as well as more 'consistent' re color temperature when purchasing a number of bulbs at a time>> Thanks, Russell <<Regards, Eric Russell>>

Lighting/HQI 10/18/07 Hey guys, <And gals> Thanks for all the help that you've given me over the past several weeks. <You're welcome.> Ever since I stumbled on your web site, I've been hooked like it was crack!!! Keep up the good work! I have just a few questions. I have a 75g with 4 36" 95 watt VHO's and I'm wanting to replace them with two 150 watt halides. I'm interested in the Coralife Aqualight Advanced Series Light Fixture with HQI - Hang on Tank Mount 150 watt 14,000k. Have you heard any feedback on these units? <I have one I use on a smaller tank, and I think it is made quite well with a virtually silent fan.> Right now I have mostly Xenia, various zoas, and a few mushrooms. What would be the best way to acclimate them to the new light and should I move all the zoas to the bottom of the tank? <I'd start with two hours per day and increase daily by two hours. Not necessary to move to zoas to the bottom unless they are on the upper third of the tank.> If I installed 2 of these fixtures, would there be any corals, clams, etc that would need more light or would I have just about everything covered? <SPS corals might have to be kept in the upper third of the tank depending on how deep your tank is. If your tank is 24" deep or more, the lighting may be border line for Crocea, Maxima, and Tridacna Clams, other clam species should be fine.> Thanks <You're welcome. James (Salty Dog)> again! Will

Metal Halide can't decide  10/12/07 Hello Crew, incredible site, Thank You for all you have done for me. But I am at a dilemma right now and I am in need of your advise. I am looking to upgrade my reef tank lighting from dual 175 Iwasakis 14K (great bulbs) to either dual 250's or single 400 watt (all electronic ballast, 10K). My tank dimensions are 36"WX36"LX 20"D, and right now it is a mixed reef tank with equal mix of softies, LPS, and SPS, but I want to go to more of a SPS dominant tank. My current lighting isn't giving much growth to my SPS, actually hardly any. I have asked several individuals and their opinions very so much that it has made me more confused. I figured with the dual 250 hang them 6-9" above the water, but with the single 400, hang it 12-16" above the water to get the proper coverage of the tank (since it is only 20"D I figured I could get away with a single 400, <You could> but if you think dual 400 watt will be best for me then so be it). I understand that there will be lighting acclimation either way f or my corals. Any advise you can give me will be greatly appreciated. Thanks Again, Mike <I am more of a fan of the single lamp/fixture here... I like the look of some light drop-off on the edges of such small systems. The Acroporids can live more directly under neath... the other cnidarians to the sides and lower. Bob Fenner>

Acrylic and Metal Halides - 05/03/07 Hello, <<Howdy>> I have a quick question. <<Ok>> I am in the process of upgrading from a 75-gallon glass tank to a 150-gallon Tenecor acrylic tank. <<Neat...  I too have a Tenecor acrylic tank (375)>> I have already purchased the tank, and I am in the process of building the stand and canopy.  The top of the canopy will be about 12" above the water.  However, this will leave my 2 250-watt metal halides about 10-10.5" above the water.  The halides will hang above the two large cutouts in the top panel of the tank.  Do you foresee a problem with the halides and how close they are to the acrylic tank? <<Not at all, especially with the bulbs positioned over the openings in the top of the tank>> Also not sure it matters but the tank is 48x24x30. Thanks, Eric <<Happy to assist.  Eric Russell>>

150W MH or 250W MH for "Mixed" Reef Tank? - 04/29/07 Hello, <<Hi Erik...Eric here>> I need some lighting help with a particular setup. <<I'll see what I can do>> I am receiving a 120G open top tank that is 48L x 25W x 32H. <<Hmm, is a bit more than 120g...closer to 160g (multiply LxWxH in inches, then divide by 231 to get the volume in gallons)>> I plan on housing the ubiquitous coral garden and hope to keep specimens from different regions and depths. <<Ah yes, exceedingly popular...and difficult to balance>> My favorite corals are LPS in the varieties Euphyllia, Catalaphyllia, Trachyphyllia, and I also enjoy some soft corals, mushrooms, and Zoanthus. <<Mmm, I see...a beautiful but nasty mix of critters.  Do be sure to space individuals accordingly and provide good skimming and chemical filtration>> This will be the first tank where I would like to try Acropora, Turbinaria, and a clam near the surface, while keeping my long time favorites in the middle, the bottom and maybe on the underside of a cave. <<Is a challenge but can be done...though I can't stress enough the need for a quality skimmer and lots of chemical filtration (carbon/Poly-Filter/Chemi-Pure/etc.)>> I plan to get a metal halide/fluorescent fixture with two metal halide bulbs and two actinic bulbs, that is horizontally mounted over the open top about 6-9 inches above the water. <<Sounds fine>> I need your help to decide whether the 150W is enough for the SPS and clams on the surface, the LPS toward the middle and the bottom, while keeping polyps and softies happy, or would it be best to go with 250W and keep polyps and softies on the underside of rocks or in shadows and let both the SPS and LPS get more light? <<The polyps and softies will also need light and won't do well on the underside of rocks or in deep shadows.  I think you could get by with the 150w halides if you kept the species with the highest light requirements in the upper-third of the tank.  But considering the depth of this tank (32"), I would likely go with the 250w fixtures for the extra bit of flexibility>> I've read too many opinions in books now, and am more confused than when I started. <<I see, you do realize that what I am providing is...my opinion [grin]?>> Some state that there is never too much light if organisms are introduced gradually to it, while others say it is overkill, unnecessary, and harmful. <<Well Erik, luckily many/most of the organisms we strive to keep are very adaptable...either lighting choice will work...'which one' is truly up to you>> Thank you, Erik <<A pleasure to share.  Eric Russell>>
Re: 150W MH or 250W MH for "Mixed" Reef Tank? - 05/04/07
You're right - I was confusing the tank and stand dimensions.  The tank is roughly 48x24x24. <<Ah yes, a "standard" 120 then>> I intend to keep a 4.5" sand bed of white sand.  With that in mind, would you change your answer or still go with the 250W? <<Hmm either is still fine, but considering this, and the fact you plan to keep organisms with moderate lighting requirements...the 150w fixtures will be fine>> I realize it is more opinion, but thanks anyway. Erik <<Quite welcome, Eric Russell>>

Reef lighting   12/28/06 My tank is currently a 44 gallon corner tank with 5 sides that was bought at like a PetCo or a PetSmart. It is pretty deep but am not at home therefore I can't give you a measurement. It currently has a 125 watt pendant supplying its lighting needs. The tank currently has various zoanthids, yellow Parazoanthus, Palythoa, various mushrooms and Ricordeas, Favia, Acanthastrea, finger leathers and toadstool leather. It also has a T. Crocea clam placed near the top in the center. It is all LPSs and soft corals but if possible a SPS or 2 later on once I upgrade the lighting. My question is how much lighting should I put on this tank? <Many variables come into consideration.> I want to do metal halide for sure but how much should I go with? Is 250 watts good or 400 watts? <I think you could get away with 250 watt, especially if you match it up with an appropriate reflector.>   I want everything to color up better and grow faster if possible. <Understandably> I do know that color was better on a few of the corals when they were in other tanks. <May be related to lighting or many other water quality factors.> So I just need to know what wattage and Kelvin rating I should go with.  I assume 10k since the clams prefer that lighting?   <Bulbs in the 10,000 K range tend to have a more complete color spectrum.  There is a great deal of variation between the reported and actual color spectrum of many bulbs.  Lots of differences in actual light output as well, depending on bulb, ballast and reflector combinations.  There is a lot that can be researched on this site:   http://www.reeflightinginfo.arvixe.com I would recommend taking some time and checking out different possibilities.>   Thanks, <You're welcome.  -Mich> Kevin
Re: reef lighting con't
  12/28/06 <Hello Kevin, Mich with you again> Ok so you think I should get a 250 watt pendant for the 44 gallon corner tank with mostly LPSs and softies? <Optimized with a reflector, and good bulb and ballast combinations, I think this would sufficient lighting.>   Would the 400 watt just be too much light or not necessary? <I think you will be more likely to encounter problems with heat and is unnecessary.> Will the 250 be enough for the T. crocea clam and possibly a few SPS? <Yes.> Now 10k is said to be better for the clam but would 14k make a difference for it? <I'd stick with the 10K, Many bulbs over this are off the visible color spectrum and not as beneficial as those in the 10K range.>      Or just stick to the 10k. I want to order the new pendant lighting system but just want to be sure if I should get the 250 or the 400. Do you by any chance know if Hamilton technology light fixtures and ballasts are any good? <I don't know, there are more than 800 bulb/ballast/reflector combinations.  You will have to check the website I refer you to find this information.   http://www.reeflightinginfo.arvixe.com>   Thanks   Kevin

MH Lighting/Kelvin Temperature/Mixed Reefs - 12/22/06 All: <<Greetings Ben, Eric here...>> Thank you for the valuable info. <<Quite welcome...a collective effort>> I am in the process of upgrading the lighting on my 125 gal. to MH 72X18X22. <<Cool!  This is my fave lighting type for reef/marine systems>> I will be getting mogul based in 20K. <<Mmm...is a matter of preference/perceived aesthetics I suppose, but unless your objective is a deep-water niche/biotope I would use something in 10K-14K.  The 14K bulbs, though similar in appearance to 20K bulbs (to us humans), will contain more "spikes" in the "warmer" spectrums enjoyed by the majority of the organisms typically kept>> I will be getting a new canopy as well, either 10" or 12" depending on your advice. <<Ok>> I wish to keep Soft, LPS and some SPS. <<Ah yes...the typical "reef garden" style tank.  The most popular yet arguably most difficult style of reef tank to maintain for the long-term...and for which there is no "ideal" lighting setup (in my opinion) due to the unnatural mix of organisms from many different niches on the reef>> I will confine the SPS to the upper 1/3. <<Likely a necessity considering the 20K bulbs>> I know these are very broad categories, but I will place specimens as they are needed. <<Ah, glad you are aware of the challenge here>> My question is; should I go with 3 X 175 watts with the 10" canopy, or 3 X 250 watts in a 12". <<Normally I would suggest the 175w bulbs as quite adequate for this depth tank.  But considering your choice of Kelvin temperature, I would get the 250w fixture for more flexibility/punch from the 20K bulbs>> I have never kept SPS but it is my understanding that 20K bulbs don't put off the same PAR as say 6500 or 10K's. <<True...some as little as half...>> Also, there is a 12", 1/2" thick center brace that one of the three lights will be directly over.  Will 10" or 12" of clearance be safe? <<In my experience, yes>> Thank You!!! Ben <<Happy to share.  Eric Russell>>

Lighting Question: SW, HQI... reading   12/10/06 I currently have a 49gal bow front tank. I have about 65-70lbs of live rock, as well as soft inverts. I have just recently switched to a 250W HQI. How far from the water surface should I have the lamp? <About a foot> I am have a pretty neat way that I have it suspended. It looks as if it is hanging from the front of a ship coming off the hanging anchor. Pretty neat!! <Sounds like it> Anyway, I am going to start (in the not so distant future)  to get some clams and other hard corals. I just want to make sure I have the right wattage and the correct distance from the water. Also, how long should I have the light on for?      Thanks, <Please read here: http://www.wetwebmedia.com/mhmarfaqs.htm and the linked files at top. Bob Fenner>

MH Q's Hello there crew,          Thank you guys for all the valuable info you've given me! <No problem :D>    Once again I'm stumped and need your guys help.  I'm looking to buy a MH lighting system for my 70g tall tank (36x18x24) with a 5-6" sand bed.  I'm looking to keep clams and SPS corals along with a Heteractis Magnifica (beautiful but demanding I know).   <Very demanding, and best kept on its own in a species tank.  These anemones can get to be a meter across, and will feel a bit cramped in your 18" wide tank!>   I've more or less decided on dual 250w 10k Ushios <I'd go with 400W for this anemone if you decide to get it-- it needs a LOT of light.  If you stick with just SPS/Clams 250 should be okay.> but can't discern what is the big difference between the regular socket type bulbs and double ended HQI bulbs.   <In general HQIs put out more light per wattage>   Either way both will run off the appropriate dual PFO ballast.  Both of  them will have reflectors and a glass cover also.  My big question is are either of them more powerful than the other?  I've read that HQI's can have higher PAR values than regular bulbs.  I've also heard they have a bluer output than traditional bulbs of the same wattage and cooler temp.  They also require a digital ballast from what I've come to understand also.  That explains the higher cost of the HQI ballast I suppose.  I like the 10k color spectrum when used alone and just need to know some of the Pros and Cons of the two formats (HQI vs. Standard). <Well for SPS corals just about any of the commonly sold bulbs will grow them just fine.  If you're looking to farm them or something I'd go with a combo of 10000K and 20000K OR 6500K and 20000K.  This is what Steve Tyree has suggested in the past.  But it really comes down to your color preference when choosing what Kelvin you get...>                            Sincerely,   Chris  AKA  ~ fishtank ~

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>

- 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 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>

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

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>

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 

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

Metal Halide Lighting Hello First of all let me say "God bless America." <Indeed> My question is, can I place one metal halide fixture on one side of the 75 gallon tank and use power compacts on the other side. <Sure> The reason for my question is to be able to keep the light loving corals on one side of the tank and the mushrooms and so on, on the other side of the tank where the light is not so intense. I am also asking this to see if there is a reason I have never seen this done. <I have seen it done once before on a 180. The left side four feet have two 175 watt MH's, while the last two section is lit by PC's. It is noticeably darker on that side, but functional.> Thanks in advance, John S. <You are welcome. -Steven Pro>

Yet Another PC vs. MH Query Hi Bob, I've read through the FAQ on lighting but can not decide which option is best for me. <begin here for starters, my friend: http://www.wetwebmedia.com/marlgtganthony.htm> I have a 72-bowfront (48Lx13-18Wx23D) where I want to keep various corals and one or more anemones (I read these really like the light).  <please do not mix motile anemones with sessile corals... it is a recipe for disaster in the long run (1-3 year picture). Inevitably one will die. Anemones truly need dedicated species tanks to be treated fairly> I'm considering a 4x55W PC setup or a 2x175W MH with possibly a fluorescent or PC actinic.  < the MH are a better route for most... more bang for the buck so to speak. The PCs simply do not penetrate deep enough into the aquarium and you will be limited to cnidarians in the top half on the tank only... may be limited by species too> This gives me anywhere from 3-5+ W/gal which is what I've always heard, but which is it?  <such rules of thumb are inaccurate and useless.. explained in article above. Pick your species first then pick your lights bud> I understand you can't compare watts-to-watts between systems, but how much light is necessary?  <as much as your selected species need... hence the need to make a guest list first. Are you keeping low light cabbage corals or high light yellow Porites? Etc> Will coral grow near the bottom of the tank with 3 W/gal of PC?  <very few species unless you plan to feed heavily to compensate> With MH, will I have to worry about what I place near the top?  <again... depends on the needs of the species you pick. Corals in the trade are collected anywhere from 0 to 80 feet at depth> Thanks for any advice you may have. Jason Jacobs <best regards, Anthony>

Metal halide I'm going to bite the bullet and upgrade to MH lights for my 110 tank. My question is this, some things I have read say I need dual 400 watt because my tank is 30 in deep...some say I only need dual 250. What says Bob? <It all depends on what photosynthetic animals you want to keep, and what you want to do with them... that you have matching circumstances to handle boosted metabolism... 400 Watt fixtures are HOT! . Please see the vast amount of information regarding lighting issues on www.WetWebMedia.com.> Thanks, Robert <You are welcome. -Steven Pro>

MH lighting for a marine 125 reef Hi there crew, Charlie here. <Cheers, Charlie> In an earlier thread, Anthony was helping a guy who was having trouble deciding which wattage to go with, 250W or 400W. I myself have wanted to go with the 250W over a 72"x18"x22" 125 gallon tank. My problem is I have about a one foot wide center brace that would sit right underneath one of the metal halide bulbs in a 6 foot x 3 MH bulb configuration. My idea is to have them make me a 6 foot x 2Mh bulb hood, with the MH being on the ends, of course. If using the 250W halides, would this be ok if I used the center portion of the tank for lower light LPSs corals? <absolutely... sounds like a very fine idea! Even a 400 watt halide would both deliver well through a thick brace (quality of light, not intensity)> Would there be enuf light in the center of the tank? <depends on species kept and their needs of course. Many will work here I'm sure: Bubble coral, open brain, Blastomussa, fox coral, Cynarina, some Scolymia, most Palythoa polyps, mushrooms, etc> I should add that this tank would be mostly SPS. <and it would be best to avoid ALL of the above suggestions I have made. SPS only will give you best chances for success. Under this center brace you can keep many Montipora species and a few Acros> It seems to me that I could get some really interesting currents goin' on in here if I thought out my powerhead head placement here, by having  maybe a large cave or just sand in the middle of the tank. <I really hope that you do not use a single powerhead in this tank (any tank). Dreadful pieces of hardware. A professional reef display will have a single return pump (or two if needed... one perhaps on a closed loop on the display proper).. external direct drive pumps. Less heat, more flow, longer lasting, better made, etc. The list of disadvantages to powerheads is staggering. They are poorly made (non-grounded plugs, some non-polarized), all impart heat, few last beyond 5 years (most less than 3 years), all leak in time (electrocution hazard), flow is laminar and not easily harnessed, multiple pumps require multiple servicing events, said pumps are ugly in the display, and the list goes on. Do consider hooking your return pump up to a teed manifold just at the water surface instead. Clean, professional, easy to service and better flow for the reef> Tell me what you guys think, I'm really looking for an interesting look in this tank. Thanx, hope you can help. Ce <have you seen my suggestions in the coral prop book for building arches and caves, suspending reef structures... and the rant on powerheads at length? Might be of interest to you. Best regards, Anthony Calfo>

Metal halide lighting Hello, <Happy Thanksgiving> My questions have to do with my 65 gallon marine tank which I want to develop into a reef system. Size of tank is 36 long, 18 wide, and 24 deep. Would a 400 watt metal halide be overkill? <it would be overkill and quite frankly dangerous for almost any common invertebrate found at your LFS> Would a 250 watt metal halide be suitable? <still possibly too much unless you are keeping only clams and SPS corals. One cannot pick their lights before deciding which coral will be kept. If you like soft corals, mushroom anemones or LPS (like open brain, elegant, octopus, hammer, bubble corals) then 250 watt is still too much.> Would a 250 watt HQI double ended be a better choice compared to 250 mogul base? <yes... a better lamp by measure> With a 250 watt metal halide would I still need to supplement with fluorescent actinic? <its not the wattage that precludes your need for actinic but the fact that all popular halides available including 6500K Iwasakis have enough actinic for corals. Keep actinics just for aesthetics if you like> And, would one light be sufficient for the size of this tank? <with a good enough parabolic (Spider) reflector... yes. A 250 watt for SPS and clams... a 175 watt for all else> Thanks much, Tim <best regards, Anthony>

MH and Oceanic canopies I'm still in the design phase of a 120 gal reef and I have been looking at the Oceanic 120 for the main tank with several Rubbermaid sumps in the basement below (more on this in future questions I'm sure). Do you have any experience with mounting MH bulbs in the Oceanic wood canopies. I appears everything will fit but I'm a little worried about having the bulbs so close to the water surface. The canopies appear to be only 6" or so tall. Thanks, Kenny <metal halide bulbs closer than 6" to water surface can be challenging... do be sure you will be keeping high light creatures that will favor this. MH though are typically mounted 6-9" off of the water surface... any higher is a waste of light/efficacy. As importantly, with a commercially designed tank, be sure that you get a model with large enough drain holes for a proper reef... too many tanks just have 2-3 holes for 1" pipe or smaller. This will be inadequate for a high light MH tank full of SPS corals that need very strong water flow. Browse through our archives on this subject (overflows) and do a google search of our site as well for such topics... there is much in the archived FAQs here. Anthony>

- Metal Halide Questions - Hi guys, <Hello, JasonC here...> I've recently come upon a 250 watt Icecap MH pendant.  My tank is 24" deep and 36" wide.  I've read that these lights only have about a 4ft square footprint so what I was wondering is, if I mount the light in the middle, could I put my LPS out to the sides? <Well... the four foot square is really more a function of the hood and reflector... but your LPS would likely be fine on the edges.> or would I need to further shield them with live rock? <This is the type of thing you will have to try and see what happens.> The animals I have right now are some brown frogspawn, a green hammer coral (branching?), a Platygyra brain, a Montipora that looked so sad in the display tank I had to give it a try (it's doing better now!, lots of growth), some yellow polyps, and some green striped mushrooms.  The light I have on it now is a 2x55w compact fluorescent hood with 50/50 bulbs.   The hammer is near the bottom, as are the mushrooms.  The polyps are on the bottom.  The frogspawn, Platygyra, and Montipora are all in the top half of the tank.  The live rock can be rearranged if need be. <Time will tell.> There's also a 1/2" thick glass strut in the center of the tank which I assume would give some shielding.  A 10k Ushio bulb is on its way as we speak.  Also, how should I mount the pendant?  12" away?  Higher due to the species I have currently? <Most likely you will want to tweak this... but higher will probably be better in your case, but probably not any higher than 12 inches.> and should it be parallel with the tank, or perpendicular to it? <Depends on the housing and reflector. Try both. While you are waiting for the bulb, check out this article: http://www.wetwebmedia.com/acclimcoralslight.htm > Always appreciating your help, Arthur <Cheers, J -- >

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>

- Metal Halide Lighting - Hello Crew, <And hello to you. JasonC here...> I have a 110 Gal 24'' deep which up until now has been fish only.  I am finally going into a reef tank having purchased a Geissmann 2x250 watt 10K MH + 2 40watt actinic PCs mounted about 9" above the water surface. I have 100+ pounds of live rock, circulation is 2 300gph powerheads mounted by the surface and a Mag 700 in the sump enough?), <More circulation wouldn't hurt.> and an Oceanic 6 Protein Skimmer (any good?). <Not familiar with that brand/type.> Now that I spent 1k on the light I can afford one anemone but it's a start.  I got a Bubbletip about a week ago and placed him about midway in direct light.  He seems fine I was told to feed him 1/2" piece of Silverside once a week (Suggestions?). <Would be better to chop that up even more so that the parts were smaller.> He ate the piece and everything seemed ok.   Now however he moved way inside a cave in the liverock not even in the light.  He's opened up but it's a little frustrating because you can't see my ONE invertebrate. <That's the way with anemones... give it time.> My question is in regard to the lighting duration and exposure.  First let me say that the 250 watt double ended bulbs 10,000K are very intense they blast away the whole house.  I wonder if they are too much hence the anemone taking cover.  I keep the MHs on 9 hrs a day (noon to 9pm) and the Actinic 9 hrs (2pm to 11pm).  Is this too much? <I think so... also, the anemone needs to be acclimated to this light. I would only leave the entire lighting system on for 12 hours, with the metal halide portion on for only eight. Additional information about acclimatizing invertebrates to intense lighting: http://www.wetwebmedia.com/acclimcoralslight.htm > The room gets light from skylights (only morning light direct into tank) also.  Are the on off time right or should they be in conjunction with the natural daylight? <Hmm, hard to say... I think perhaps you should let the sun do it's thing and then extend that photoperiod with the metal halide, perhaps kicking in right when the sun's intensity via the skylight starts to fade. You probably don't need more than eight hours of this type of intense light so adjust all accordingly.> Should the light be higher off the surface. <Nine inches should suffice.> Any suggestions would be appreciated. Tanks, Rich <Cheers, J -- >

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>

MH lighting Hello, I have question on MH lighting that i want to buy... it's 250W 20K bulb Hamilton Metal halide. <actually... the True 10K German lamp from them would be better for most corals> I have 55 Gallon and currently running NO 80W 10k and blue actinic light over it.. <yikes! 250 watt lamps are too bright here> i have xenia, mushrooms, and polyps.. is this a good idea to buy this metal halide (of course, local guy gave me really good deal.)? <the lights are way to bright for the size of the tank and the corals being kept. Less is better here my friend. Two 150 or 175 watt lamps would be better> thank you always. <best regards, Anthony>

MH on 125 Damn, I hate doing this. I feel like a pest. Hope you don't mind, but I wanna do this right. <no worries, ask away> You aren't the first person to tell me that. Being on a budget severely limits me. <hmmm...seems that is the case for most everyone!> I was afraid of this from the time I switched over from freshwater plants and CO2 injection. How much more could running a FOWLR be I said (yeah right). Well say I can use some of the tax money (wife allowing). Would two 175 Watt Hello Light pendants be enough on a standard all glass 125? Or should I retro my hood and keep some of the old NO bulbs for added light? <Does this mean you would modify the existing hood for the MH? That would be the way I would go. Don> Need to just bite the bullet I guess. Thanks again...

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>

MH lighting Just a couple of quick questions after I thank and congratulate you on a wonderful site.  I am here at least 1 hr a day reading and absorbing.  Don't know what I would do w/o this website and your support now. <Thank you!!!> Ok.  In a couple of months I should be ready to start ordering supplies for my new 75 Gal system.  I had originally planned on 1 175W MH bulb w/ 2 110W VHO Actinic White bulbs and 1 110W VHO Actinic Blue bulb. However, I just read in 1 of the facts that 1 175W bulb should be used for every 2 feet of tank, so should I change my setup to 2 175W MH bulbs and 1 each of the VHO lamps since my tanks is 4 feet long? < It would be better to have the 2 metal halides, you may also want to consider dropping the white VHO and having 2 actinic VHO's with the 2 halides> How far above the water level do u recommend mounting the lights <8-16> and do you need some sort of clear barrier between the lights and water?  <yes> Oh and 1 last thing, is there a way to submit a question other than e-mail? <Nope> Thanks in advance for all your assistance and please keep up the great work.  You just don't know how much it means to beginners. < Thank you!! Keep those emails coming, Cody> Jeremy

3, 175 watt MH enough I just purchased a used 150 gal tank and plan on making it a reef tank...this tank is the long type and is only 24 in high...will a triple 175 MH hood be enough for most corals? Rob < This will be fine for many LPS and soft corals.  If you want SPS I would upgrade to 3 250 watters. Cody>

Lighting - VHO vs. MH Hi Bob,  We currently have a fish only 110 gallon system. The tank is 30" tall x 48" long and I am interested in improving the lighting of the tank. Although, changing the lighting is not required for fish, we are considering going into corals in the future. Currently, the tank is lit with (2) 40 watt fluorescent bulbs. What is your opinion of a (4) 96 watt bulb VHO system versus (2) MH bulbs at 175 watts each.  <The VHO is better all the way around... Compact Fluorescents would even top the VHOs...> What do you think the economics will be for running the four VHO tubes versus the two MH bulbs. <Cheaper to run in the long haul by far... likely no need for a chiller...> Using only the MH bulbs, will the full required color spectrum be available or must this system be supplemented with other fluorescent lights? <Better to supply some actinics via fluorescent> Thank you for taking the time to answer my questions. Jim H. >> <You're welcome, Bob Fenner>

Lighting Hey, I want to convert my fish and live rock tank to a fish and invert. tank. I am going to buy a wet dry filter and put my existing protein skimmer, heater, and UV sterilizer in the sump that is attached to it. I plan to buy 50 more lbs of live rock (to make a total of 85lbs) and get rid of my coral loving butterflies. My main problem is lighting. I plan to keep clams, algae, and maybe some soft corals. I have a 54 gallon corner tank with 40 watts of lighting. The problem I have with power compacts is that I can only fit in a 24 inch long fixture. So if I got a power compact like the one from all-glass it would only add 15 watts more of lighting. I am pretty sure that would not be enough lighting. What do you think would be the right amount of lighting? <For the mix of life you list, size, shape of tank... about 150-200 watts... and this is possible with retrofit kits and some clever installing... do look at the parts for sale here and there on the net... FFExpress.com, the many good company's listed in the hobby magazines like FAMA> So I am left to VHO and metal halides. I have read about two kinds the normal and some sort of mercury filled kind which seams to be more economical as far as replacement bulbs go. I figure a 175 watt or 250 watt bulb would be enough light. The VHO lights would put me at 150 watts with 2 bulbs in a 24 inch fixture. Please send me your recommendations on what you would use in my dilemma. <Dilemma? This is a tremendous opportunity for growth Jonathan!> Thank you, Jonathan Pac <A metal halide along with some actinic power compacts could work here, and be very attractive... and yes to seeking out cost savings... Do make provision for alleviating waste heat problems... Likely having a splash tray arrangement with your sump/wet-dry, maybe with added air (from an air pump) and steady/daily make-up for evaporation will do. 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>

Cloudy Water Orangetailblenny here bugging you again. (sandy) I read up on the material you suggested, and as much as I want a clown trigger I guess not. I'm real dumb on this lighting thing for the wet pets . Soooooo would you talk to me like a 4 year-old on the light my fish need in a 55 gal. cube shape (square) tank about 1 yd. deep? (Yikes... a meter-yard deep? Probably a pendant or two of Metal Halide... Please read over the Marine Lighting, and Light sections on the www.WetWebMedia.com site... the sections are simple enough that even I understand them...!) I gotta tell you bob:::::::you do every thing I dreamed about doing when I was young. my hero + john Wayne. ha :::::::::::::::::::ta and see you in the sea-lol:::::sandy (Hmm, wish you were here (visiting in Baja's end the last few days)... cold, surgy, not so fun for diving, pix... but manana is another day. Bob "Duke" 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>

Light ? Hi, I was wondering if you have any experience with the custom sea life prism pendant (175w MH / 2 32w CF)? <A little> I have a 65 gallon tall tank (34x18x24) and I was wondering if this would be enough light to keep anemones and corals like the bubble coral?  <Should be, yes> I currently have the tank set up with a 110w CF with some leather corals and mushrooms and I don't have much room in the canopy for any more CF's. Thank you, Trevor <Make it known how your conversion comes out. 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>

Water Quality, Air Bubbles and MH lights on too long Hi Bob, <Anthony Calfo in your service> Seems to me that water hardness in a marine aquarium should be high.  <yes...relatively speaking> I didn't realize this at first and was shocked that the water was way off the scale on GH and KH. Is there a point at which this is too high? <11-12 dKH is very fine...approaching 18-20 is scary if you have a reef and you are dosing calcium for fear of a crystalline precipitation> Secondly, I've got a 65 gal tank with 30lbs of live rock, 1" of large crushed coral,  <thin this out if you don't siphon it frequently> some snails, shrimp, and crabs. Its been up for 3 months not doing much. I've had a sump connected, but removed it due to gear problems. I've got this annoying bubble problem. First I thought it was the sump, and to some degree it was, but now all I have is a power head that is submerged 10" from the surface and a heater and there are still bubbles.  <sticking to and emanating from the rockscape? If so... lights may be too bright or on too long> I thought it might be the water quality (see above), <no way> but I've done some large water changes (30% x 2 in 2wks). Everything else water quality wise is good. The only other problem that I seem to have is algae. This started when I put on the Metal Halides over the aquarium.  <hello! There's your answer. MH bulbs closer than 12" (not necessarily bad) or on for more than 9 hours daily (more likely and possibly unnecessary) are often culprits> This in tandem with the addition of some tap water and pure circulation and no protein skimmer.  <Aiee! you're killing me. No skimmer?!? Why don't you just cut one of my fingers off instead...hehe. You will continue to have serious algae problems in all likelihood without a good and functioning skimmer> I've got the skimmer now (EV-120) and waiting for the pump.  <nice unit> I've purchased a 5 stage water RO/DI Unit which should be the cat's meow.  <agreed> I've also purchased a great sump return pump. When it all get here I start up the sump again. <sounds like it will be a nice setup...have faith and patience for it to come together> Any ideas why I've got so many bubbles? Puzzled? <no doubt in my mind that you have your lights on too long... I've seen this with hundreds of aquarists in the past decade. Kind regards, Anthony Calfo>

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 acclimating my corals to MH. <for acclimation tips also look at my article on WWM: http://www.WetWebMedia.com/acclimcoralslight.htm> In terms of my 90 gallon reef tank, I want to include clams to my microhabitat, thus the reason/need for MH.  <would be nice, but not at all necessary... even the most demanding crocea and maxima species would live nicely in the top 10" under VHO and the like> Would adding 2x-150 watt 6500K Iwasaki bulb with 130 watt of PC actinic be more reasonable/applicable?  <actually sounds very nice and would satisfy most popular inverts (great for many Zoantharians, soft corals and LPS)>  What are some ways to allow my corals to adjust to the 2x-150 watt MH?  <all spelled out in the above listed article> Lastly, can you recommend a ballast brand that can operate the Iwasaki bulb (all I have seen are Ice Caps, and PFO---which I think makes Ice Caps)? <hmmmm... I'd have to look into that. I'm a bit out of the loop on all brands to comment> Again, thank you very much for your time. Cheers, Dan <kind regards, Anthony>

Hello, It always amazes me how quickly you guys respond...the entire WWM crew's dedication to this hobby deserves much praise! <Thank you very much!> To recap our last correspondence, you are in favor of the Iwasaki 6500K MH and a standard ballast. I have follow-up questions in terms of wattage for MH, a reliable ballast, and acclimating my corals to MH. In terms of my 90 gallon reef tank, I want to include clams to my microhabitat, thus the reason/need for MH. Would adding 2x-150 watt 6500K Iwasaki bulb with 130 watt of PC actinic be more reasonable/applicable? <That sounds like a good mix. Iwasaki's for photosynthesis and actinics to improve the aesthetics.> What are some ways to allow my corals to adjust to the 2x-150 watt MH? <You can temporarily have the lamps raised and then slowly lower them. Also, keep the MH's on for a short time period, say only two hours and add two hours every week until you have reached a desired photoperiod, about 10 hours. The PC's can be kept on for 12 hours daily. And lastly, you could try shading the tank with several sheets of vinyl window screen to cut back on intensity, removing sheets later.> Lastly, can you recommend a ballast brand that can operate the Iwasaki bulb (all I have seen are Ice Caps, and PFO---which I think makes Ice Caps)? <They are two separate companies as far as I know. You should be happy with either. I would refer you to various articles written by Sanjay Joshi in which he compares ballasts and spectral outputs, http://www.personal.psu.edu/faculty/s/b/sbj4/aquarium/aquarium.html> Again, thank you very much for your time. Cheers, Dan <You are welcome. -Steven Pro>

Lighting a 180g Tank Guys, I wrote about a month ago about lighting my 180g tank. Bob encouraged me to look into halide lighting for hard corals and tridacnids. After much reading and talking with lighting guru's, most recommendations point to the use of double ended (HQI) bulbs powered by electronic ballasts. There were many claims that the double ended bulbs are much more intense per watt than traditional, single ended bulbs. I have not found any articles out there, that have done any technical test to prove that claim. <Take a look at the articles written by Sanjay Joshi, a professor Penn State. His website is here with links to several of his works http://www.personal.psu.edu/faculty/s/b/sbj4/aquarium/aquarium.html> If any, what are the benefits of double ended bulbs. Would you consider 3 250W @ 10000K (with actinics) be sufficient for the more demanding hard corals and tridacnids? <Sounds like more than enough.> It is also my understanding that double ended bulbs do not have a U.V filtering, outside envelope. <Correct> In a DIY project, how would one come by UV filters. <See if Sanjay mentions it in his piece. Most units I have seen come with the filter built in.> Thanks again for many answered questions. I'd give away my mom's Chitins 'n' Hot Sauce recipe to be able to get the reef lighting right the first time around...JS <Have a nice weekend. -Steven Pro>

HQI lighting Hello, I currently have a 120 gal reef (48 x 24 x24) with a variety of SPS, soft corals. Due to my 430 dollar a month electric bill (Thanks Gov. Davis!!) <$430...whew! Consider a cheaper hobby... like drug abuse> I recently removed the two 250 watt MH bulbs from the tank and replaced it with a 4 x 96 watt Power compact hood ( 2 actinic and 2 10,000 k bulb) and also have 2 110 watt VHO Actinics. .  <Hmmm... perhaps not a great savings all things considered. 400 watts of MH light compared to 400 watts of PC light are not the same. MH is far more intense=more bang for your buck. Your corals are getting MUCH less light (easy to confirm with a Luxmeter at the surface and even more so at 12" water depth> I also have a 300 gal marine fish only tank and had an outside 60 gal grow out coral tank which had the power compact set up I just mentioned. Anyways, by getting rid of the 500 watts of MH from the 120 in addition to breaking down the outside 60 gal, I lowered our electric bill by over 200 bucks!!  <excellent... but has less to do with the lights... perhaps as much or more with pumps/heaters removed> The corals in my 120 include: star polyps, colt, pink Button Coral, mushrooms, green finger, hammer coral, Fox coral and green pin leather. Anyways.... Some of the green corals (star polyps, green finger) have turned a little brown since I took of the metal halides. I have been told that I may have too much light which is why some of the corals are turning brown?  <yep... predictable. Lower light has stimulated the zooxanthellae (brown dinoflagellates) to increase their resident populations in symbiosis. a common and perhaps harmless change> I think that under the metal halide the green corals looked their best (had 500 watts MH, 220 watts VHO actinic and also 80 watts of regular flourescent)800 watts total now down to the 384 (pcs) and 220 VHO which is just over 600 watts. Now for the question. I would like to go back to metal halide supplemented by VHOs but want to go with a much lower wattage, like two 150 watt HQI dbl ended bulbs? <the double ended bulbs have got some great reviews> I am researching the HQI ballast/bulbs because it seems to be kind of new still and now a lot of info is known. I am still looking for the article by Sanjay Yoshi but have not found it yet.  <a keyword search of Sanjay's name on the Google search engine for WWM and abroad comes up with many hits for his work all over the net. Please explore the first link for his general homepage and the second link for one of his very good studies/articles. More o be had if you will explore: http://www.personal.psu.edu/faculty/s/b/sbj4/aquarium/aquarium.html  http://www.personal.psu.edu/faculty/s/b/sbj4/aquarium/ballast%20comparison/ballast-comparison.html > Anyways.....is there a difference between a dbl ended bulb versus a screw type? I saw a 150w HQI ballast (made in Taiwan) it takes a screw type bulb. I have read and heard that the dbl ended bulbs burn brighter?  <they do have a great early reviews> I would just have to worry about the U.V lens? <usually necessary> I am considering going with the 300 watts of HQI metal halide supplemented by the 220 watts of VHO actinic and maybe additional 80 watts of actinic. I realize if I put back the 80 watts of actinic plus the 220 watts of VHO actinic I am back to 600 watts of light,  <hmmm... so many lighting choices, but I am content with tried and true solutions. All of the better rated "regular" MH lamps have been shown to have enough blue/actinic light and require NO supplementation. If you want a simple solution, choose 2 or 3 6500K Iwasaki 150 watts (or 2 250 watt lamps) or the same number of 10K Ushio or Aqualines if you like a bluer colored daylight. Extra fluorescent lighting will only be for aesthetics if you like> If I don't I am cutting back about 80 watts. But would the intensity from two 150 watt HQIs put out more lumens than the 4 x 96 PCs?? <yes... MH type bulbs in general are far more intense... better deals> I will be searching for some HQI ballasts (Champion Lighting, Hamilton etc....) to compare to the Taiwanese made one I saw at my local fish place. If you have any opinions about the HQI ballast/bulbs versus the electronic Ice Caps MH ballasts or standard coil/tar ballasts could you please share your opinions with me. <fine with cap and coils.. I am strongly against electronic metal halides based on published and yet unpublished reports I have seen. Misleading and inaccurate marketing of these products> Again, I am very concerned with my electric bill so I am thinking that by using 300 watts of HQI instead of the 384 watts of PCs may help and also make the tank look a little brighter and some of the green corals get their intense greens back? <correct> Thanks for your time. Kerry Kanno <best regards, Anthony>

MH Lighting I would like to know your opinion on Metal Halide lamps 175w. I am starting a 55 gallon reef tank and want to know what kind of lighting I should buy. <I would use some sort of fluorescent lighting, normal output, power compact or VHO depending on corals housed.> I want to put lots of mushrooms, polyps, soft and hard corals (a wide variety). I wanted 175w 14000K but champion lighting does not sell it because of some technical problem. What do you think about 10000K? <These color temperatures are mostly marketing.> I noticed two different kinds, Ushio and Aqualine. Any opinion would be greatly appreciated! <Both are very good, but I would not use MH's on a 55. MH's produce a great deal of light and can cover a 2' x 2' area quite well. Your 55 is only 12" wide. You will end up lighting a lot of your floor.> Also someone advised me to buy 2 175w 20000K for my 55 gal reef tank, what do you think about this? I want my tank to grow, grow, grow and to be beautiful and healthy! Any advice would be great! <Four normal output 40 watt lamps would serve you well for mushrooms, polyps, many soft corals, and LPS corals. For SPS corals, I would use four 55 watt PC lamps.> Thanks, Nattalie <You are welcome. -Steven Pro>

MH Lighting Hi, I am planning on upgrading my tank size from a 55 to a 120 (48x24x24). I currently have about 15-20 frags of SPS and assorted LPS. I am stuck with the decision between 2-250 watt 6,700K Iwasakis w/ 4-96 watt actinics or 2-250 watt 10,000K lighting with actinics. Can you make a recommendation on which combination you think will be more effective in maintaining colors in the SPS while having a crisp non yellow coloration. <Really, with actinics, either should be fine.> Can you also make a recommendation the best ballast for Iwasakis and the MH I am interested in, and the best manufacturer of 10k bulbs. <Please see here http://www.WetWebMedia.com/marine/setup/lighting/mhmarfaqs.htm and here http://www.personal.psu.edu/faculty/s/b/sbj4/aquarium/aquarium.html> Please feel free to let me know if there should be any changes in the combination of MH and PC color temps. <Seems fine.> I would greatly appreciate any information. Thank you, David PS: If your ever in Miami, FL look up Aquariumart (my place of employment) <If we ever get down there, we will try. Thank you for the offer. -Steven Pro>

Metal Halide Hi guys, can I use a standard Hibay metal halide ballast and reflector for aquarium lighting, if so how many watts is too much, my aquarium is a 125 gallon reef and I have two 400 watt units. Thanks, jjk <I would never recommend to for most any aquarium, although I favor MH lighting. 400 watts is an obscene and potentially dangerous amount of light for aquaria less than 30" and for anything there except for some SPS and clams. A few hardcore aquarists have lucked out with these lights but most aquarists struggle with stressed animals under these lamps. Even 250 watts if too much for most systems. There have been some complaints too about the industrial fixtures exploding some aquarium designer lamps or not firing them at all. Despite all of this, the light you pick ultimately depends on the livestock selection. You must pick your intended corals before you know how to light them! I personally wouldn't take this fixture for free... too many hassles. If your tank is simply 24-30" deep and you want good lighting... buy a 175 watt 10K Aqualine MH lamp for every 2 feet of aquarium length. You need no other bulbs/actinics, etc. Best regards, Anthony>

Reef Lighting  Aloha, <Greetings.> I have a 75 Gallon tank. I am not wanting to take a shortcut on lighting. I want to keep some SPS and clams. I keep my house cool (about 70 degrees) I will have 4 - 4" fans in my custom enclosed canopy over the tank (hanging pendant- style out of the question unfortunately). My canopy will be about 8 to 12 inches over the tank. I plan to purchase a sheet of polished aluminum and line the entire inside with it. <I'd get it at least coated with something... aluminum and saltwater don't mix well.> On to the lighting... I would like to retrofit 2 - 175watt 10,000K metal halides.  Complementing that, I can either buy an Icecap 430 and run 2 110watt actinics, OR I can purchase a 660 and run 2 110watt actinics PLUS 2 110watt 10,000K bulbs along with the halides. Is this overkill? <Hard to discern... you probably don't 'need' the extra 10K fluorescents.> Again, I would like a T. maxima or T. crocea in the near future. But I don't want to burn the SPS corals. <Make shady areas with the rock work OR drop one of the metal halides and light with the other on one side of the tank only, and then perhaps use the 10K VHOs on the side that doesn't have the MH lighting.> OK, if you're still with me, back to the MH. I have heard about UV rays, so I assume I will have to build some sort of UV lens for my MH. <That is correct.> Is this a special type of material or could I use a piece of acrylic? <I would use glass - acrylic will likely melt being that close to a lamp. Glass is available with a UV-filtering coating.> I could build a " box" over each bulb with it. Not sure if the bulb would melt it though. <It would.> I really don't want a piece of glass or acrylic over my entire water surface. I want evaporation for Kalk top-offs and cooling factor (with the fans blowing across the top of the water). <You might need to rethink this, with fans sucking hot air out of the canopy.> I am trying to come up with a plan to where I do not have to use a chiller, but get sufficient lighting. <I'd skip the canopy and instead light from above with adequate space for more fans. You will soon see that the canopy becomes a trap for heat, and you largest problem will be getting the heat out of the collector.> I have so many ideas in my head so if you could blindfold me, spin me around 15 times and point me in the right direction, that would be super cool groovyrific!! <Again... if SPS is part of your goals, then skip the second MH. Light that side with only fluorescents. You will still have issues with heat... you may need more fans or you may even need a chiller. Time will tell.>  Mahalo, Jason <Cheers, J -- >

Acclimating to Metal Halides Hi, Love WetWeb but I am little confused as to how I should acclimate a new lighting system. I currently have a 75gal with mostly LPS and soft corals. I am currently running 4 65watt pc lights with one 18k standard fluorescent. I have noticed that the deeper I place corals the worse their health gets. I read over and over lighting requirements for this size tank and I really think the best way to go is Metal Halide especially if I want to experiment with SPS corals. I am looking at getting 2 175 watt 20K metal halides and I am going to run these with my 4 pc lights all actinic. What is the best way to introduce these new metal halides? I was going to start high (about 20" of the water surface) and gradually lower. But then I read that you can start with 1 hour of light for the first day and increase this by 30 minutes every day until you reach the desired cycle time. Which one do I use I am confused. Thanks.....<Terry, either way is OK.  James (Salty Dog)>

MH lights and coral growth 4/14/05 Dear Anthony <Cheers> I am upgrading to 250 watt halides (Arcadia series 3). These are going pride of place over my 130 gallon mixed reef garden setup. I have the following corals 1 Montipora 1 frogspawn 1 Euphylliid (hammer) 1 Montipora 1 Turbinaria several Caulastrea colonies 1 sun coral 1 Pavona various Sarcophytons <Hmmm... overall a moderate (light) needs tank. It will be good/better if the 250 watt lamps you use are 10k - 20k K in color> All are placed away from each other and at heights specific for the genus, allelopathy is reduced by regular weekly water changes and regular preening of the softies. My existing light setup is 5 60 watt VHO lights and 1 T5. My question is really what should I limit the halide photoperiod to? <6-8 hours will be fine here for MH> Water quality is fair and I get fabulous growth from the Pavonas and frogspawn and Euphylliid. Not so much growth from the SPS hence the reason for the halide upgrade. <Hmmm... you are a bit mistaken here, perhaps. Water flow (increase) and feeding (try DTs Natural Diet for your SPS corals) are much greater influences on coral growth. Increasing light alone will not improve growth in many cases> My wattage is essentially doubling so I know I have to go gentle with the adjustment. <For this gentle acclimation, do a key word/phrase search for "screen method" here in our WWM archives :) kindly, Anthony>   

Lighting Opinion  11/16/05 Hello All, Just a quick question, I have just upgraded my lights to (2) 25 <Likely 250> Watt HQI Retro kit from CA over a 4ft. 100 gallon tank 2 ft deep. I raised my canopy so the lights are about 10" above the water and have installed fans that keep my water temp. and canopy at or around 79 degrees. The light appears to be a lot brighter but I think it looks nice I went with 15,000k CA bulbs as the 10,000k were just a little too yellow for me. Is this too much light? I have the following: Ricordea (mid bottom of tank) Flower Pot (bottom of tank) Pulsing Xenia (all over) button polyps (top) 140 lbs of assorted live rock 3 inch live substrate Thanks, Paul <Should be fine... I do hope/take it the change was done, is being done over a number of weeks. Please read here re: http://www.wetwebmedia.com/acclimcoralslight.htm.  Bob Fenner> 

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