Metal Halides for Nano Reef
I have a 12 gallon reef tank that has a water depth (from surface of water to top of sand bed) of about 15".  The dimensions of the water surface area are about 9.5" by 14.5".  Right now, I only have a Power Compact fixture putting out 36 watts (18 watts daylight, 18 watts actinic).  I read Anthony's article, "Lighting Your Marine Invertebrates:  Reef Lighting Without Controversy!", so I won't get caught up in the watts-per-gallon talk.  However, I do realize that my setup is somewhat underpowered.  This is evidenced by my faded and washed out looking squamosa clam.  Its colors used to be very distinct and bright, but now they have faded.  Also, nothing in the tank looks as if it is really thriving...just existing.  I really would like to upgrade my lighting, and I really want to replace my existing fixture with a metal halide setup.  I'd rather be limited by space rather than lighting issues as I want to be able to add just about any coral to my tank (especially those requiring high-intensity light).  Problem is, I don't know exactly what wattage bulb I would need and how high to place it given my water depth.  What are your recommendations?  If it makes any difference, I actually have a total of about 17 gallons since I incorporated a 5 gallon sump to hide the bulk of the machinery (heater, skimmer, etc.).  Initially, I was looking into getting a garden grow light, ballast built into the pendant
(http://dansgardenshop.com/sunsysiv100w1.html), that puts out 100 watts.
Your thoughts?  Also, if MH isn't the way I should go, would it be advisable for me to double my wattage by putting another 36 watt PC fixture adjacent to the one I already have?  I was looking at a JBJ clamp on unit (http://www.jbjlighting.com/sys_clamp_on.html).  Will that improve my situation?  The tank I have is more tall than wide so it kind of puts me at a disadvantage in terms of finding a high PC wattage bulb that will fit over the tank and w/n my custom-built stand.  Any advice would be much appreciated.  
<Hmm, I think the MH would be too much. Although I have seen some 70W MH and that would be more appropriate. If you do decide to go with the pendant you reference, then make sure the bulb is the proper temperature. MH would be mounted 8-12" from the surface of the water. I think the additional 36W of daylight (rather than half/half) is the way to go. The clam may take to being further up in the tank (closer to light source) and that will help.
I would not recommend mixing corals with different needs in any tank. Stick to a group that has like habitat needs. They (and you) will be much happier>
Hope this helps. Don>
Sandy

250 watts or 150 that is the question? Sm. SW...  05/02/2008
What is up crew....
<<Hello, Andrew today>>
Do you guys think 250 watts MH on a 10 gallon nano is to much light? Or should I go for a 150 watt MH lamp?
<<150w is more acceptable, 250w will more than likely cause negative effects such as bleaching, burning>>
I am going to be running a chiller that is rated for 50 gallons on my nano. And of course I want to keep Acros and Montis. What light should I get???
<<Stick with the 150w, that is ample lighting for this tank when considering size and depth>>
Thanks crew
<<Thanks for the questions, hope this helps. A Nixon>>

watts per gallon
Hello,
Can I keep Acros in a ten gallon tank with a 145 watt MH lamp? Do you think 15 watts per gallon is enough?  4/19/08
Thanx (ps) Killer site!!
<Can be done... with careful acclimation of stock, the use of an (expensive) chiller... Do read on WWM re Acroporid Systems, Metal Halide use... Bob Fenner>

MH Lighting on Nano 11/30/07
Hello there everyone,
<Hello, Scott V. here.>
Quick questions about lighting. I have a 12 gallon AP that is modded with a chiller, has 24 lbs of live rock in it and used to use stock lighting of 54w PC's.
http://i117.photobucket.com/albums/o46/mynd/AquaPod/PB270009.jpg - tank I have recently upgraded to the Coralife 24" 150w MH with Dual 65w 03 actinics and moonlights. I run the actinics 10 hours a day and the MH's 6 with a pre 2 hour and post 2 hour actinic sunrise.
<8-12 hours a day (probably on the lesser side here) would be preferable with the halide, with actinics one hour before/after.>
Moonlights are on for the other 14 hours. I know they say that you should have at least 3 – 6 watts per gallon on your tank in lighting. My first question is as follows.
Is the equation for that as easy as taking total wattage 280w and dividing it by the amount of water ( 10 ) gallons in your tank? Meaning I would have 28w per gallon?
<First of all, I would not factor in the actinics, leaving you with a mere 15 watts per gallon! Small tanks like this are where the watts per gallon rule really lacks. If you follow 5 watts per gallon, this leaves you with 50. This may be adequate for mushrooms but any more light intensive corals will suffer, the intensity is just not there towards the bottom two thirds of the tank. I personally think your light is a good choice considering that you have a chiller.>
I currently have the lighting fixture 12 inches above the tank and it is 21 inches to the bottom of the tank from the light. What do you think the optimal amount of inches from the top of the tank would be so that I could get optimal results / color / growth for my mushrooms, Zoa's, Palys and acans along with a small piece of Hydno. The Hydno is at the top of the tank about 14 inches from the light and doing well. The MH's are 14k.
<21” from light to the bottom of your tank is just right for your light.>
I have no desire to do SPS but might consider a maxima 1" clam in the future.
<Maximas this small are fairly delicate and tanks this small are inherently unstable. In addition the clam will outgrow this tank. I would leave the Maxima out of the equation and concentrate on growing out the frags you currently have.>
I would think with this lighting that there is really nothing I can't put in there within reason.
<Yes, the lighting could, stability in the other parameters and room will be the problem.>
Currently the corals are frags and growing so I am not overstocked. What are your recommendations for the above mentioned? I enjoy commentary so throw in anything you think is relevant.
Thanks!
<Welcome, have fun, Scott V.>

Re: MH Lighting on Nano 11/30/07 12/18/07
Wow, thanks for the information.
<Quite welcome.>
One last question this week ;) and Happy Holidays to you and your family.
<Thank you.>
If you have a MH fixture like I do which is the Coralife 24" 150w HQI MH with dual 65 watt 420nm actinics and 2 1watt 470nm LEDs, is the air space above the tank considered a loss of light area? So if you place the lighting fixture 8 inches from bulb to water and 13 inches to the bottom of the tank is that a total of 21" or would you only be using up 13" of the 18" maximum depth of a 150mh fixture?
<The bulb to substrate is what is ultimately going to count. But, it is typical to run halides 8 of more inches above the water.>
I am just wondering for people who have tanks that are like 24 inches deep and potentially 21" from water to bottom of tank and potentially another 9 inches from bulb to water if they are exceeding the limitations of let's say an 175w MH HQI? Or should they go with 250? All Softies.
<With softies the 175 will do, with clams and Acros I would have to say go with the 250.>
Hope that made sense.. Read it twice if you have too.. lol..
<It did.>
Thanks again!
Kind regards,
Stephen
<Welcome, happy holidays, Scott V.>

Lighting change, small SW  9/13/07
Hey Crew,
I currently have a 26 gallon, believe it or not, amazingly beautiful flourishing Acro only tank.
<Can be done>
1/10 ViaAqua chiller
Nano Remora Skimmer
PhosBan Reactor
Carbon Chamber
Various species of Acropora, Lilleopora, Staghorn, and Montipora
One False Percula Clown hosting large Emerald Mushroom happily!
150 Watt CoralLife HQI Pendant, which is not working properly any longer.
<Describe if important, germinal...>
I have an Aqua Medic 250 Watt HQI which I would love to be able to utilize, and of course save money on.
<Save money?>
I have always used 20K XM bulbs, and my coral love them, they are bright purple, blue and green...
I would be using the 250 watt HQI with a 20K XM bulb, and would place it much higher from the waters surface. What are your thoughts? Overkill?
<Likely so... but worth trying if it saves having to buy another fixture... except for the higher energy use, temperature influences...>
Best regards,
Ronnie
<Bob Fenner>

Re: Lighting change – 09/13/07
Good point about the energy usage. As for heat transfer, a small fan, fixture distance from water's surface, and chiller should do the trick...
>Ah, yes<
I am moving the 26 gallon to a larger 60 gallon Oceanic reef ready system in about a month, however, in the meantime, these corals need light. SO the 250 will have to do for now.
Thanks so much for your time, no need to reply.
Ronnie
<Be seeing you. BobF>

48w 10K 50/50 replaced with SunPod 70W HQI, Sm. SW light/burn episode   7/5/07
Your web site seems to be the most knowledgeable on the net so here goes:
I just replaced 48w 10K 50/50 with SunPod 70W HQI on a 12 gallon nano cube I have established for two years.
The tank primarily contains different soft corals that had blossomed under the 10k 50/50 with coralline algae growing everywhere. Since placing the SunPod on this tank (only two days), everything seems wilted and is not as vibrant and alive as before.
<Ah, yes... a lack of photo adaptation... All "burned">
Please advise.
My goal was to remove the canopy and add a little extra light. I'm not sure what is happening but want to get advise.
thanks, Philip
<Please read here: http://www.wetwebmedia.com/acclimcoralslight.htm
and the linked files above... And elsewhere (learn to/use the indices, search tool) re lighting small marine systems. Bob Fenner>

Lighting, flow, and warfare.   5/24/07
Hello, thank you for taking time to answer my questions, I have 4 years fowler
<What's the "e" stand for?>
tank experience and around 2 years of reef (let my tank sit for about a year before I really added anything of significance), I have a 40 gallon reef and a 30 gallon sump, equipment as follows: 1-175 watt MH, 195-watts of VHO, according to my flow meter there is around 2195 gph coming out of my sump, a modified SeaClone skimmer that does a decent job (I only skim a week or so out of the month, and shut it off once the skimmate is light in color), and I have a hang on filter that I use for carbon (again a week or so out of the month). I have 2.5 inches of sand in both sump and display, 70 pounds of live rock in the display and around 20 in the sump. I do 10 gallon water changes every couple days (Sunday, Tuesday, Thursday), is this ok?
<Likely so>
I have a colony of candycanes, a Millepora, a Stylophora, two Acroporas, a capricornis, an encrusting Montipora, and two other plating Montiporas, all around 3-4 inches in length and are growing like crazy. I also have some xenia (why did I put it in there?!), a toadstool, and a few mushrooms and zoo's that sprouted out of my rock. I plan on increasing my light and getting rid of most of my soft corals, and sticking to SPS. I was planning on adding one more 175 watt MH but I found a PFO dual 250 watt MH ballast for $50 more. Would this be overkill or do you think this would be ok/worth the extra dollars?
<For a forty gallon system? Overkill. If you use this, you'll definitely need to buy/run a chiller, get sunglasses for all who live there>
I have a lot of overhangs in my tank so if some of my SPS do not like that much light I could easily shield them. I would like to add quite a few more species of SPS, but I am worried about warfare, thoughts?.
<Posted>
I am also setting up a 29 gallon/20 gallon sump for my Mother's birthday and I was thinking I could put my softies in there with the 175 watt MH from my tank if I buy the dual 250, good amount of light?.
<About right for this shape/depth>
Being a poor college student, I am trying to do this cost efficiently (wrong hobby), what would you suggest for flow rate for a soft coral tank of this size?
<Also posted...>
Also, should I switch my skimmer to this tank and increase the volume of my water changes to compensate?
<Maybe... I'd test the water/s so to speak... as time goes by...>
Any other tips you could relay would be great as well. Thanks for any help you can give, you guys are amazing, and I greatly appreciate it.
<Please learn to/use the search tool, indices on WWM. Bob Fenner>

Mushroom Garden, 20" cube and HQI lighting  - 04/20/07
Hi Crew,
<Good morning>
I have read your article http://www.wetwebmedia.com/marlgtganthony.htm and the page on corallimorphs. I am also reading Bob Fenner and Anthony Calfo’s book "Reef Invertebrates" (Absolutely Fascinating) and have read Eric Borneman's book "Corals".
<All good books. Published print is still a very valid medium>
I am setting up a 20" cube, open top, with 20" cube sump / algae refugium / miracle mud. No skimmer, low bioload. 20X turnover but flow will be dissipated with wide bore return to display, reduced flow bypass to Fuge (how much flow to fuge?) Live rock and 1/2 inch sand in display.
<The flow to the fuge depends on the return pump used and the diameter used for your display drain, the GPH?>
I want to keep all different kinds of mushrooms (my passion) Zooanthids and star polyps. Don’t like SPS or LPS.
<Nice to hear some variation, these corals are also very easily kept, and propagated adding to their environmental/sustainable worth>
My Problem is Lighting. All sources agree that mushrooms like low to mid light levels but how does that equate to a 20" cube? I can’t get tubes or luminaire to fit 20" tank so was going to go with a HQI pendant. Also I like the glitter line effect. My LFS says 150W but I’m worried the mushrooms will fry. People say put them at the bottom but the tank is only 20" deep and if you want a mushroom display then you want them everywhere. Do you think a 70w HQI would be better? Or go for 150W raise them up higher ? What Kelvin, I’m thinking 14K? (I’ve not actually seen a 20K  working in the flesh and I’m not sure if it would look too blue).
<I think that a HQI pendant would work fine here. The 150w would maintain these corals very well, without frying them if a suitable height was used; I would aim for around 8-10 inches and note the effects then raise or lower accordingly. The 70w would also work but I often find it hard to obtain good bulbs here in the UK for this wattage. Also I feel you may wish to branch into SPS/LPS at some point, most people do, and the 150w will allow you to accommodate some of these without the need for an upgrade. On Kelvin ratings, I use 14k bulbs and I love the colour however with the fluorescent qualities of many Zooanthids and Corallimorphs, the 20k bulb may show these off better. I must add they can appear quite cold though.>
Tank is still being made and I’ve not made any other purchases yet so best to get it right from the start. Your recommendations would be greatly appreciated.
<Hope I’ve helped. Just out of interest, which company is building your tank?>
P.S The above books have been a wonderful inspiration and wealth of knowledge please thank Bob and Anthony.
<Bob will get your praise and hopefully pass it onto Anthony> <Yes, thank you. RMF>
Rachel, UK
<Olly, also from the UK…Frags anyone heehee>

Re: Mushroom Garden, 20" cube and HQI lighting   4/24/07
The tank is being built by Wharf Aquatics in Pinxton, Nottinghamshire.
www.wharfaquatics.co.uk
<Ha! As I predicted, say hello to Tom for me, guy with white hair, I’ll be known as young Olly I’d imagine. A brilliant business>
It is having no stretcher bars to spoil the clean lines and they are using black silicone and blacking out the back wall and weir in black acrylic.
There will be no visible equipment.
<Had my tank built here, wonderful quality, couldn’t stretch the extra £90 for black silicon unfortunately due to the size>
And yes you really have helped.
<Glad to hear it, what we’re here for>
I am going to try to buy only aquacultured specimens as there really is no need to take these from the wild as they are so widely propagated. Eventually I hope to propagate myself ( the corals I mean, not actually myself, my husband does that)
<Heehee>
Many thanks for your reply
<Pleasure>
Rachel Mason
Nottinghamshire UK
<HaHa, it’s a small world. I’m from Nottingham as well! I have mushrooms available, self-propagated but that’s another matter. I would stick with Wharf also, although I am not here to promote businesses, their knowledge and experience will serve you well, they're genuinely there to help - a wonderful company. Good luck with all your endeavours and would be nice to hear back from you, Olly>

Reef Lighting 3/28/07
I have a 36 gallon corner tank that I want to begin an SPS tank with.  I was looking at lighting options and wanted to know if 150w HQI Metal Halide would work.  I kow that people say more is better, but with 36 gallons and a 21" tank depth, I did not want to have heat issues.  I do not want to purchase a chiller and was wondering if SPS would thrive under 150w.
I've searched all over and everyone seems to have an idea about what works best for them.  Some people even chose T5 lighting, but I've heard bad things about this as well.  What do you think?
<SPS corals do best under MH/HQI lighting.  I've just started using a Coralife Aqualight clip-on.  The only drawback is that you cannot mount it in a hood.
This light has a built in cooling fan (very quiet), and comes with a 14K lamp.  Is a very well made system and my corals have reacted favorably to it.
If you must use a canopy, you will not find an HQI strip light that will fit a 36 gallon corner, at least none that I'm aware of.
In that case, you will have to get a retrofit, and a fan will be necessary.>
Thanks for your time,
<You're welcome.  James (Salty Dog)>
Shane

Re:  Reef Lighting 3/29/07
Jimbo,
<Shano:)>
The opening of the 36 Gallon Corner is 23".  I was looking at getting a 24" Current SunPod 150w.  It is a strip light.
<OK, so there is no wood canopy.>
The other thing I was looking at, but quite a bit more for money, was the Coralife light which is an HQI/PC combo fixture. Both fixtures are 150w and should fit atop the 36 gallon with little difficulty.
While I agree, SPS will probably do better under MH lighting, my question is, will the 150w be enough for a 36 gallon, 21" tall tank?  Is 250w your recommendation or will 150w do the job?
<If you like a bright tank, the 250 watt would not be overkill, but the 150 HQI would work well.  I'd place the light loving corals (SPS) in the mid to upper
levels of the tank.  The Coralife fixture I referred to is a 150 watt HQI.  I'm using this
fixture on a 40 tall mini reef (20" high).  I personally like the Coralife clip-on because it allows me to do maintenance without taking the
fixture off, making it much easier to clean when I can see what I'm doing.  If your tank is less than 12" wide, which I doubt, you would not be able to adjust the light to be in the mid section of the tank with this fixture.  Take a look at it here.  http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=13922&prodid=27192&catid=115  James (Salty Dog)>
Shane

MH lighting over shallow tank  3/6/07
Hi WWM crew,
<Hello Jackie.>
I would like to thank you for all the information you share.
<Welcome.>
I have a question about lighting.
<Okay.>
I am going to go from a 29 gallon reef tank to a 40 gallon reef tank. I would like to keep some higher light loving corals and want to step up to a metal halide light. The 40 gallon tank is only 16" deep and I plan to have only a ½" sand bed (I have a 20 gallon refugium with a 6" sand bed). Will a 150 watt 10000K double-ended HQI metal halide be too much light for the 16" of water depth?
<Can work, suspend the lighting at least 12" above the tank and make sure you can keep up with evaporation and maintain the proper temperature.>
Thanks,
<Welcome.>
Jackie
<Adam J.>

70W MH enough for SPS? Halide on a Nano?    02/17/07
Hi WWM crew. #1 problem solver online for me! I have a question, would the 70W MH be enough to keep a couple, maybe 2 or 3, Acro's in an aquapod12? Thanks
<Yes but there are heating and stability issues to be addressed...Adam J.>

Lighting/Reef/Metal Halide  - 04/25/06
Hi.
<Hello Danny>
I am wondering what wattage Metal Halide bulb to use over a 29 gallon. I mainly want to keep Tridacna clams. Possibly an SPS or 2. The tank is 18"
tall and 30" long. I have about 20 pounds of reef sand and 35 pounds of live rock. I want to go with the 250watt 10,000k halide but my LFS says it will create too much heat. <Yes.> So, my question is, should I go with the 250 or the 175watt?
And what color bulb would you recommend?  <Danny, I'd go with a 175 HQI system. Here is a link to an on-line dealer selling such a system for $169.00.  My dealer has received some PC fixtures by this company and he considers them very good quality for the buck.  I like 14-20K lighting for a reef system.  OK, here is the link.  http://www.aquatraders.com/index.asp?PageAction=VIEWPROD&ProdID=217&HS=1>
I am experienced in keeping marine and reef tanks but have always had PC lighting. This is my first venture into Halides and due to the cost, I want to
buy the right setup the first time. I can't really find alot of info on Halides over a 29gallon. BTW the tank is plumbed to a 10 gallon refugium. I know
it's not a large tank but I am diligent in research and maintenance. Any info would be appreciated. Thanks for your time.
<You're welcome.  James (Salty Dog)>
Danny R.

Nano and Metal Halide Lighting... Nano Soup?  - 05/17/2006
Good Afternoon all,
<Late night now, Hi.>
First allow me to preface by saying I am relatively new to this hobby,
<Welcome.>
but have I have been reading all I can to get up to speed.  
<Superb.>
My current set-up is a stock 24 Gal. JBJ Nano Cube DX with the standard 72w of PC lighting.  I currently have stocked;  
-                     One (1) Wellsophyllia 4.5"

-                      One (1) Flowerpot
<Not an easy species….rarely live 6 months in captivity.>
-                      One (1) Pod of (8) Blue Mushrooms
-                      One (1) Trachy Brain 2.5"
-                      One (1) Crocea Clam 2.5"
<Not a great choice for a nano or power compact lighting.>
-                      One (1) Multi Headed Torch Coral
-                      One (1) "Green" Finger Leather Coral 5"
-                      One (1) small candy cane coral
-                      One (1) small pod of Zoa's
-                      One (1) Coco Worm
<Ditto on the comment about the flowerpot.>
-                      One (1) Regal Tang 2.5"  
<Not a great beginner fish, and inappropriate for this size tank.>
I have read that the corals will benefit from a Metal Halide 10K-14K light source and that the color will be more intense.  If this is true, I would like to remove my stock hood and install a Current USA SunPod 150w 14K.  
<In my opinion to much heat and light on such a small volume of water…and to be honest your animals barring the clam will do fine under your current lighting.>
This unit has legs and will be perched 4" - 5" above the water's surface.  So, is the benefit worth the cost and am I going to create too much heat (current water temp 79.1 F. with heater)?
<There are ways around heat but if you are new you may want to wait before you attempt to deal with such.>
Thanks for all of the advise.
<Adam J.>

Metal Halide, Shallow Tank, and Clams - 06/12/06
Hello, hope ya'll are having a fine morning.
<<Mmm, yes...for a Monday>>
Just got back from my bachelor party so I can't complain.
<<I see>>
Anyway, there is a lot of advice out there as far as the appropriate wattage/mounting depth to correlate with certain tank depths, but I can't seem to find any that fit well enough with my situation.
<<Much left to personal opinion/subjective interpretation>>
Currently I have a 250W double-ended HQI MH lamp with 14k bulb.  My aquarium is a 40g flat-back hex with a depth of about 20" from top to bottom.  After accounting for substrate and unused space, the greatest depth any of my charges can be possibly kept is 16".
<<Okay>>
My lamp is mounted approximately 8.5" away from the water surface.
<<If your corals are acclimated to this lighting then this is fine.  But considering the wattage of the bulb/depth of the tank you could easily move it up several inches...in my opinion>>
With the use of a fan heat is kept within sane values (78 degrees).
<<Much to be said for evaporative cooling>>
I'm worried though that this might be too much light.
<<Depends on what you are trying to keep>>
My coral charges seem fine and quite happy with the new arrangement.
<<Then likely nothing to worry about>>
My T. crocea (which I received shortly after) did expel some zooxanthellae right off even though it was placed in the bottom of the tank,
<<More likely due to shipping/handling stress, than lighting>>
currently it seems fine (mantle spread, not gaping) and I have had it a week now.  My main concern is for my smaller juvenile T. maxima (w/ darker gold coloration).
<<Any Tridacnid species under 2" is problematic (seem to be especially susceptible to shipping stress/problems with acclimation)...best to obtain these clams at 3"-4" in size for the best chance at keeping them alive>>
Is my concern misplaced, as these are light loving creatures, or should I consider raising the lamp considering the depth of my tank?
<<What is the clam telling you?  If it seems happy and healthy then leave as is.  But I also think raising the light a bit won't "hurt" anything if you should so choose>>
The T. maxima seems to be happier on the whole since I have started using a sodium nitrate solution.  It concerns me though that no matter how much I add I still seem to have 0 nitrates.
<<Likely used/removed very quickly...be sure to make increases in small increments...and keep a sharp eye out for the start/increased growth of nuisance algae>>
Could this solution be taken out by a skimmer or PolyBioMarine's Poly-Filter?
<<Yes>>
It doesn't seem likely, being a salt, but my knowledge in that area is pretty limited.
I'll appreciate any knowledge you wish to pass my way.  If perhaps I have missed this information in your faq, I apologize.
<<No worries mate>>
Thanks for your help!
James Tanis
<<Cheers, Eric Russell>>

Metal Halides, Webmail Lateness - 07/04/2006
I just want to start out saying thank you for such a great web site.  
<Thanks for this kindness.  Let me firs apologize for the delay in this reply; seems as though your email came to us in a state that few of us are able to view/respond to.  My system allows me this privilege, fortunately.>
My question is somewhat simple.  
<That's the kind I like!!>
I want to upgrade my lighting in my tank. Currently I am running a power compact with two 65W 50/50 lights.  I have wanted to upgrade to a HQI Metal Halide but don't know how much light I really need for my tank - And if I may be getting too much. Some specs on the tank: 30gal tank with 50lbs of LR, have a 12 gallon refugium. Currently I only have Soft Corals, Mushrooms, Polyps, things in that nature.   
<These do NOT need extreme lighting....>
I have been looking into getting a 150 watt HQI metal halide with a 15,000K bulb, is this a good choice?
<For your softies and corallimorphs?  No....  too much light, in my opinion....>
Will I be able to keep Hard Corals with this lighting condition?
<Not in the same system with loads of soft corals and corallimorphs.  Best to go one route or the other; too much allelopathy.  If you do choose to retain your softies, 'shrooms, etc., try at least to not have "too many", and plan on using lots of chemical filtrants to remove (or at least decrease) the amount of chemical toxins they release.>
Also when I upgrade the lighting I'm afraid that some of my current corals may not adjust well.
<Agreed.>
Should I just reduce the number of hours the light runs for; say from 11 hours to 7 hours and gradually increase over time?  
<Best to raise the light a ways from where it will ultimately be located, and slowly (over days) lower it.  The farther it is from the tank, the less light your animals will receive - this, in my opinion, is better than dropping it right on 'em and decreasing the amount of time lit.>
Thanks Ron
<All the best to you,  -Sabrina>

High Light Situation...Nano-Reef Aquaria   7/4/06
Hello
<Hey.....there.>
, I have a quick question i
<I.>
want to ask.
<Sure.>
I just purchased a new JBJ K-2 Viper 70 watt metal halide light for my 12 gallon nano.  
<Lot of heat on a tank that size.>
This is the only light I'll be using over the tank.
<Umm...that's all you'll need.>
How long should I leave it on everyday?
<What is the targeted photosynthetic livestock? You be attempting to emulate the habitat, artificial or natural (assuming it is coming from an appropriate habitat) the specimen is currently in. As a general recommendation, I would say a minimum of 6 hours and a maximum of 12, 7 would be a nice median.>
Also, when should the bulb be replaced?
<You should be using a light meter to monitor the lumens, but again generally speaking about 12 months. Give or take a bit (or alot!!!) depending on the ballast, bulb and quality of the reflector.>
Thank you!!
<Adam J.>

Help with DIY MH... 7/21/05
I have been thinking of getting a metal halide system, but do not have the money to actually buy one... so what I've decided to do is make my own using some existing equipment i am currently using. First off, I have a 130W Odyssea PC (Jebo) with one 12K bulb and actinic bulb. I've looked at many metal halide systems and have noticed they had this running as well. So, my thought would be to combine these with a metal halide.
i would like to first ask everyone where to start when looking into a DIY metal halide system.
<OzReef.org>
So far, I know
I need 12gauge wire,
<Mmm, maybe something thicker...>
a ballast, the DE bulb, and two connectors to each side of the bulb. My question would be what to look for in a ballast (what brands), what's the difference between the 20k bulb vs. other bulbs, how many watts should i need for a 20 gallon tank. I've never done a DIY for anything, but the price for a prebuilt one is ridiculous.  I would like to try and incorporate the ballast into a section I've found that's empty inside of the PC. I want to try to put the bulb in the center of the entire thing beneath the two PC bulbs also adding some aluminum reflectors to it. Would I need to take off the acrylic sheet that blocks the light bulbs from everything else? Thanks for the help.
<... well, first off, I would not use MH technology on such a small volume/system... second, know that these units can be very dangerous... exploding lamps, UV burns, fire... I strongly encourage you to look into boosted fluorescent lighting instead. This is all posted over and over on WWM... Bob Fenner>

MH Question - 07/23/05
I was wondering if you guys could give me a good idea of what I should do for my lighting.
<<Depends largely on what livestock you intend to keep...but I'll do what I can.>>
I have a Oceanic 30 cube that I just want to put my 150 watt Aqua Medic HQI over.
<<Sounds fine so far...>>
The thing is I think 10K bulbs are too white, and the 20K bulbs are too blue.
<<Disagree on the 10K, agree on the 20K.>>
I was wondering what bulbs you think are better the 12K, 14K, etc... And out of them what brands you trust to buy from...
<<My preference is 10K, but if you really don't like the looks of a true 10K then my recommendation is the Aqualine Buschke 10K bulb (hold on a sec!).  The AB 10K is more "blue" than others (closer to a true 13K) ye still quite "bright", and the AB brand bulb is an excellent product.  If by chance you decide to go with a true 10K, then my recommendation is a Ushio bulb.>>
Thanks -- Nathan
<<Regards, Eric R.>>

MH for 37 gallon set-up 7/21/05
I would love to have suggestions for lighting a 37 gallon tall tank.
Approximate measurements (30 long X 12 deep X 22 tall).  I currently have a 3 year old 25 gallon tank with refugium that is flourishing with soft corals and 3 fish (clown, coral beauty, mandarin) with a 130 watt PC from Custom Sea Life.  
I "inherited" the 37 gallon with fish included (7 total).  Currently I'm lighting the tank with an old 110 watt PC hood.  I've added a 2-4" sand base - but nothing else.  It's been circulating for 2 weeks.  Enough background - I want to create an environment to house SPS and more light needy corals that I have stayed away from for my 25 gallon.  I love the look of MH and would love to have suggestions.  
<A small wattage (no more than 175) pendant...>
One obstacle on the tank is that there is a 1" wide black plastic bar in the center of the tank on the top running from front to back.  I'm afraid a bulb in the center of the tank would cast a bad shadow into the tank.
<Place the light a foot or so above the tank, slightly off-center>
Any suggestions are very much appreciated and welcomed!
Thanks - Cheryl
<Welcome. Bob Fenner>

New Halide distance over water surface - 8/01/05
Hey guys how are ya all?
<Thanks Aaron, we are good, hope you are in good health as well...>
I have a question concerning lighting. I have a 29 gal reef tank with 2 Percs right now. I am currently running around 4 watts per gallon of PC lighting. I bought an anemone from my LFS about a month ago because it was looking shabby and they would sell it to my at next to nothing. So now I want to order the Coralife HQI/PC combo fixture. That will give me 9.7 watts per gallon.
<150 watt/250 watt? Species of anemone?>
I was wondering if I acclimate the tank very slowly to the new lighting will they burn? I want to house a vast array of corals and 4 watts per gallon just wont cut it. I also need to hang the fixture about 6 inches from the surface and was wondering if this would cut back on its efficiency.
<Depending on the intensity, I would even recommend raising the bulb 12" and slowly decreasing it an inch every 3-4 days until you reach 6" or so. Do a search on coral lighting acclimation, there's a ridiculous amount of information here.>
Thanks for your time,
-Aaron
<Good luck - Ali>

Marine lighting 8/28/05
Hi Bob, <James today> I would like to know what you think of the new Coralife 150 watt halide that mounts onto the tank. It is a 20 k bulb, I was considering putting it on my 42 gallon hex tank to keep mushrooms, polyps and possibly a bubble anemone. The tank already has two true percula clown's, a four lined wrasse, and a golden angel, 30 lbs of live rock and a CPR refugium with skimmer built into it. this is a hard tank to get multiple lights on because of the dimensions . What do you  think is the best lighting for this type of tank?  What are the pro's and con's of  halides or my other choice pc's, thanks Ron from R.I. <Ron, the 150 is a nice light, but in your 42 hex I'm afraid it wouldn't be enough to support corals and an anemone.  It is just giving you a little over three watts per gallon and we should be looking a four watts+ per gallon, especially being the hex is a fairly deep tank.  Hex's are really not a good tank for keeping corals, etc for this reason and the fact that the surface area is very small in relation to tank volume.  James (Salty Dog)>

Lighting MH  1/10/06
Hey All, <Hey Jenna>
Do you think I should get a second MH 400w pendant for my 50 gallon reef so I can have one on each side of the aquarium?  I find that my SPS are not as colorful on the sides and along the bottom of the tank...
Or, should I purchase a Current 2x 150HQI double ended fixture?   
Reason is, I can get a good price on it, but is it not enough light for the SPS? <On a 50 gallon tank the Current System is the way I'd go.>
Any thought would help.  I really want the corals to grow faster, and show more color.  When I buy them from Reef and Fin in Connecticut, they are gorgeous, after awhile, they seem to fade a bit in my tank.   
I am aware that many factors could be involved, but my water is awesome, and I am doing everything I can to keep these animals under   optimal conditions...<You must also use supplements such as strontium, iodide, calcium, etc to accomplish this.  I say this since you didn't state the use of such.  James (Salty Dog)>
Thanks so much. <You're welcome>
Jenna

Metal Halide Retrofit - 02/07/06
WWM Crew,
<<Howdy>>   
I have a 46g bow front with the plastic hood/canopy in place.  Currently I am running the Coralife 2X96 watt PC system with integrated cooling fans, I should also mention that I have  approximately 7" clearance from the top of the hood to the surface of the water.  I want to upgrade to MH lights most likely with a retrofit system, what are my options to make this happen?
<<Mmm....remove the hood and replace with a 150w MH pendant...maybe something similar to this: http://www.hellolights.com/aqadhatamo.html ...Regards, EricR

150watt metal halide. too much light?/Sunglasses for Corals  - 01/24/06
Question for you guys. Thinking of upgrading my lighting system for a 16 gal. nano reef. running for 3 years now) As of the moment using a 64 watt pc set up. Freakish amount of zoanthids, they are growing like crazy, dropping new little colonies all over and spreading over everything. totally cool!) <Great!> I have a few areas on the live rock that has Porites doing nicely, growing and spreading out also. Also about a 4 inch wide area  of Monitpora covered by a slight overhang. The Montipora is starting to lighten up in colour in the area that is under the overhang <Move it?>(duh!). Adjusting the rock to allow more light creates a very unstable rock formation. <Can use underwater epoxy cement.> My now long winded question is. would a 150 watt MH set up (aqua-medic mini pendant) be over the top in the light or would bumping up my pc set up to 128 watts be a safer direction. i.e.: little less heat,<Yes> less intense for the other inhabitants.<I'd opt for the 128 idea giving you eight watts per gallon, more than enough to keep most anything.> Would rather not blind myself/family if pendant needs to be a lot higher from water surface to avoid the heat build up, and end up wasting light.
Any blunt/ honest info would be a huge help.( eyes are buggy from reading and talking to suppliers about this. some are all for it others are nuar.geo the pc route..)<James (Salty Dog)>
POG

150 watt metal halide. too much light    1/25/06
COOL!, thanks for the speedy reply, <Just lucky, you were in the line of fire.> I will try the epoxy idea for the rocks,
the rock the Montipora is on is a flat thin piece, sort of the middle center piece of the display but.." if can if no can no can"... again thanks for
the freaky fast reply.. and for the wicked site, amazing resource for info!. <You're welcome.  James (Salty Dog)>
Aloha POG

Metal Halide Lighting    4/10/06
Good Morning, <And good morning to you, Steve.>
First I would like to thank you all for taking the time to share your experience. You all have been extremely helpful in the past. <You're welcome.>I have a question regarding metal halide lighting. I currently have a 29 gal tank that I am in the process of setting up. (mini reef) (I will be moving the
inhabitants of a 20 long into it.) I am looking into upgrading my lighting to a 175 metal halide. I have searched on-line auctions and have found some
really good deals. Most of the cheaper systems include a magnetic ballast. I have found other systems with electronic ballast for more money. Will the
magnetic ballast be louder than the electronic ballast? <Yes.> Are there any other benefits to consider? <Electronic ballast provide more energy savings, slightly brighter light, longer lamp life, and reduced noise.> I don't have a problem spending a little extra to buy a better product. I just would like to know what the difference is before I make the purchase. Also will the 175 watt be sufficient? <Yes, would allow you to keep any coral/clam you wish.> I could upgrade to 250 or 400, but think this would be overkill for such a small tank. <Yes, much more heat also.> (I do plan on adding some actinic lighting and fans to ventilate my canopy also.)<A must.>
Thanks for taking the time to guide me.  <You're welcome.  Do read here also, Steve.
http://www.wetwebmedia.com/marine/setup/lighting/fixtures.htm
James (Salty Dog)>
Steve

Question about lights and center brace
I have a 37 gallon tank (30x12x24) that has a center brace.  The center brace is about 2 inches wide and made of a brown plastic, not a clear material.  I would like to light this tank with a metal halide fixture.  I was thinking about a single 250w HQI pendant.  My two concerns are that the ends of the tank won't get enough light and that the center brace will block a lot of the light and give me a large shadow.  The main reason I want to use this light is to keep some Tridacna clams, and then maybe some corals.  Do you think this setup can work, and if so, how high off the water should the light be to cover the entire tank?  Thanks  Rob
<Yes, the set up will work but there is not much you can do about the shadow that will be cast.  I would make sure that you have a decent reflector and raise the light to at least 12 to 18 inches from the water.  That is the best you can do with that tank.  good luck mikeb>

Lights for a 44 gal pentagon tank
Hello-
< Hello >
I have a 44 gallon pentagon corner tank.  I'm just getting started with a saltwater tank...have some live rock and damsels only at this point while the tank cycles.  Eventually I would like to add some soft corrals and the like.  Since most lighting fixtures with high wattage don't fit on the top of my awkward tank, I was advised at a local store to get a hanging metal halide light...250 watts for my 44 gallons. < May not be enough light, but I do like the advise of hanging halides. >  I was reading some of the FAQs on your site and your advice seems to indicate that 250 watts is too much (also, they advised me that the light should hang 6" from the water).  Please advise on the proper lighting system for my needs...36" deep tank, limited space on the top. < I'd say at least one 250 watt halide, and then a couple VHO actinics.  You may not get the VHO to fit, so in that case use some pc actinics. > Thanks!
<  Blundell  >

HQI lighting
Hi, <Hello>
I really enjoy your site...I've received some great information that has helped me to set up my current reef tank.  My question is this: I have a 30 gallon hex tank that is 25" tall and 18" at it widest point.  I want to convert this into a reef tank so I was planning to hang a metal halide pendant over it in order to light it.  I have a choice between a 150W HQI metal halide or a 250W HQI metal halide.  Which one should I choose?  Since this is a hex tank, I was planning on doing without any supplemental actinics.  I was hoping to get by with just one 14K HQI bulb.  I plan to be keeping mostly zoanthid polyps, xenia, a few clams and a frogspawn in this tank.  I would like everything to grow quickly, but I am worried about burning or bleaching some of my corals with too much light.  Any suggestions that you could give me would be much appreciated. <My choice would be the 150 HQI. Shouldn't have any problems with this.  I would keep it about 4" above water level.  James (Salty Dog)>
Thanks for your help!
Nishat

MH Pendants - How Powerful? - 05/07/05
Hello-
I was wondering if in a 50 gallon tank, one 250watt metal halide pendant would be too much light for a frogspawn and other LPS corals?
<That's the thing about pendants, their height above the tank can be easily adjusted to vary light intensity in the tank.  You can also place organisms with lower light requirements towards the ends of the tank...assuming the pendant is centered on the tank.>
I wanted the 250 watt MH because I wanted to keep a lot of clams.
<You can get by with less wattage.>
Could I get away with clams in a 50 gallon tank with one 175 watt MH pendant?
<Most assuredly.>
I am interested in the Coralife MH pendant either 175 or 250 watts which would be better for a tank with clams and LPS corals?
<I would go with the 175w, save a little on power consumption.  Or better yet, a 150w DE pendant...great little light.>
Thanks, -Will
<Welcome, Eric R.>

Choosing a Metal Halide for a 46 gallon Bow - 5/5/04
First off - FANTASTIC website! <Thanks> I can spend hours on end reading up on things completely losing track of time. <Me too. Now I volunteer here> The team's dedication and willingness to help is nothing short of incredible. <I agree. They have been very supportive of me as well. I continue to learn a lot>
I am upgrading lighting on my 46 gallon bowfront tank (36x15x20). I am looking at hanging a 2x175 13000K MH w/ 2x96W 7100 PC about 8" above the tank. <Sounds fine> My hope is to keep a nice mixed reef tank with soft, LPS and SPS corals. Further down on my priority list is maybe putting a clam on the sandbed at the bottom. <OK>
Will this light fixture suffice? <I believe so. Just as a side note, I have a 250 over a 20 gallon. It is hot (California) but with a fan blowing over the top of the water as well as blowing over the light, I can keep the tank around 80.8 easily. Gotta top off often though>  Someone said a 2x250 MH would be necessary for clams, <Not for clams. I have seen great clam growth with VHO, T5, PC and of course various other MH. Intensity of the lighting source (PAR output is very important to sustainability of zooxanthellae and photosynthesis. (=survival for corals)> but I'm worried about far too much heat in the summer time (in California). <Could use a fan blowing across the water or lights. Also, look into a chiller. I use an Aqualogic controller to monitor my heating and cooling. A great tool and worth the money if you can afford a fan or the more expensive chiller. I believe your setup will be fine for whatever you choose. I like a mixture of either 6500K bulbs and 10000K bulbs if you have two MH systems. you might like a bluer look and you could put Actinics in the PC system if you want but in my opinion I would go for the MH and forget the PC entirely (unless you already own it)>
Thanks! <Thanks for being part of it all! ~Paul>
Shaun

Small metal halides
  Hey guys.<Hi, MikeD here> I have a 46 gal. bow front with a 4 39w t-5 lamp. I would like to add some metal halide lighting but I only have about 4 inches of room behind the t-5's to work with (I was out voted 1 to 1 on drilling holes and hanging a pendant) what is the smallest fixture I can buy to fit in this space (4x36). I thought I had good lighting but my green star polyps were green when I bought them and they are more brown now. my colt leather looks great but I figure extra light can't hurt.<My suggestion would be to possibly add another power compact as I'm afraid a MH would overheat a tank that size VERY easily. That's a LOT of heat that you're contemplating in a very small space>

HOW MUCH HALIDE IS ENOUGH? 6/30/04
Hello,  I am currently setting up a 24"x24"x24" acrylic cube tank to house a 10" anemone, it is one of the carpet anemones, haddoni or gigantea?  Will be basically a specimen tank designed specifically for the anemone and some black percula clowns. (can more than two perculas be kept together).
<Kudos for having the discipline to maintain a species tank for your anemone.  Please do be sure to positively ID your anemone as Gigantea and Haddoni have different preferences and Gigantea gets quite a bit larger  Both can grow to sizes that exceed the size of your tank.  "Anemonefishes and Their Host Sea Anemones" by Fautin and Allen is an outstanding resource for this topic.  Keeping more than two Percs in such a small tank is probably risky.  If you do attempt it, let a pair get established and then introduce a much smaller new comer.>
Would I be better off with a HQI metal halide 150W pendant or a 250W  HQI pendant?
<150w will be fine if you maintain excellent water clarity, but I would probably choose 250w.>
Also 10K Aqualine or 20K Aqualine bulb?
<Very much an issue of personal preference here.  The 10K will provide much more intensity, but if you prefer a deeper blue appearance, choose the 20K.  If you choose 20K, I would definitely recommend 250w to make up for the lower intensity.>
Hang it 9" of the top of the tank?
<Should be fine.>
Other than the live rock/live sand and percula's, any suggestions as to what else can be kept in this tank , a clam? dwarf angel? etc., or better yet what not to keep in this tank?  Thinking of the long term.
<S. Haddoni generally buries it's foot in sediment and Gigantea will occasionally do the same, so I would go with a deep bed of fine sand.  Other sessile inverts are probably OK, but keep that discipline and don't go overboard!  Shrimps, crabs, slow moving fish (mandarins, gobies, etc.) are all definitely out.  You are in a catch 22...  Your tank is too small for free swimming fishes, but the anemone makes it to dangerous for smaller less active swimmers.>
Thanks for your time and expertise, Stephen
<Glad to help!  Adam C.>

Metal halide over an acrylic tank 9/1/04
Hello WWM crew!
<Howdy>
I currently have a clear-for-life 30g show(36"Lx12"Wx16"H)set-up with mostly zoanthids, mushrooms, Ricordea, and one candycane/trumpet coral.  There is also a 20g long AGA aquarium under the main display serving as a sump/refugium w/ tons of pods.
<very nice>
While I currently have 130w PC's for the main display, I recently purchased (but it is on back-order now) one Aqua Medic 150w 20,000K Metal Halide HQI pendant.  
<a proper wattage... and the light is rather blue, but still fine as long as you stay with these polyps and deeper LPS corals. Else stray closer to 10k K lamps>
I plan to have it approximately 10" above the water level.  
<a bit too high... 6-8" would be better most likely. But do check the spread of light once mounted>
Will this pendant be sufficient for my set-up (i.e. will it actually reach most of the 36" length of my display tank?  Or should I order another one and have 2 of them hanging above my tank?
<Yikes! two would be one too many. One MH is fine here bro>
Secondly, as you probably know, the acrylic tank only has 2 rectangular openings at the top of the tank and right now I have an acrylic cover that came w/ the tank over the opening.  Will I need to leave the acrylic cover off for the metal halides?  
<nope... not if the MH comes with its own lens, and it almost certainly does>
Just worried about evaporation issues.  
<inevitable... and its a chance to bring more Kalkwasser in to the system?
Will the metal halides damage my acrylic tank due to the heat issues?  
<not if its high enough. over six inches should be fine>
Thanks in advanced for any input.  I've followed a lot of your advice on your site and my tank has been thriving thus far because of it!  Thanks again! -Dennis
<best of luck, my friend>