Lighting Overkill? 1/23/08
I currently have a 65 gallon, 36x18x24, I already have 2 150W halides with 20K radium bulbs. I would like to upgrade to a system that has 2 250W 10K halides with 4 T5 actinics. This would give me around 656W, but that is over 10 watts a gallon. I plan on housing more sps and clams in the future. Should I stick with this idea or go with a less wattage of halide, like 2 175W mogul with T5's.
<I would be inclined to stay with your current fixture with bulbs in a better (10K) spectrum.>
I currently have DE bulbs and the lighting in question has DE bulbs. I currently have just polyps, some micromussa, a tort, purple fuzzy and a BTA. Would like clams to live in the tank, 2 died under the 150W's.
<Not enough “usable” light with the 20K.>
I'm having a big problem deciding. Thanks for your patience. Also, no heat issues right now, but will I have serious heat issues if I do go with the 250's,
<Quite possible.>
Thanks
<You will realize a large increase in light your corals/clams can use with the simple switch to a lower wattage bulb. Two 250W would be overkill in my opinion considering it is a three foot tank and the lights will overlap quite a bit. The 175W would be fine, but again different bulbs in the 150W fixture would be the way to go considering the lighting will overlap. Check out the link below, noting the difference in PPFD (Photosynthetic Photon Flux Density; what your corals use) between the 10K and 20K bulbs. Welcome, hope this helps you decide, Scott V.>

Using Heater Controller For Controlling Halides 12/26/07
Hi Crew,
<Hi Tom>
We're leaving for a few days of vacation
<Take me with you:)>
and are trying to eliminate some of the many possible failure points in our 130G reef tank. One worry is that the chiller could fail and allow the halides to cook the tank. Have you tried using a heater controller to cut power to the halides if the temperature gets too high, like this one: http://www.championlighting.com/product.php?productid=21402&cat=389&bestseller
Seems like it ought to work. I searched WWM for "halide" and "controller" but didn't find any similar references.
<This product is not intended to do this and I doubt very much if it would provide the inrush current needed to start the lamps. Other problems can/will occur as well.
Be safe and do not use this product for that intention, you may be looking for a home when you return.>
Thanks,
<You're welcome. James (Salty Dog)>
Tom

MH Lighting, Acrylic Tank, Very Low Canopy...Not The Best Recipe – 10/18/07 Greetings, <<Morning>> I've found a lot of useful information on your website, but after reading countless FAQs, I still can't come to a decision on lighting for my tank. <<Oh?>> I'm currently in the process of setting up a 400 gallon reef tank (96"L x 30"W x 36"H). <<Cool!...love big reef tanks...have a 375 myself>> I've got just about everything I need except for the lighting. <<Okay>> It's an acrylic Tenecor tank with two 25" x 15" top openings on both sides, with 21" between openings and 13.5" on either side length wise. <<Mine too is a Tenecor built tank, though I had them “customize” mine with three openings in the top versus two to make “lighting” the reef easier...as you are no doubt discovering with that 21”-wide center brace. In retrospect, I wish I had spent a bit more money and had the top thickened and the bracing/perimeter reduced...but I digress...>> I've got about 275 pounds of live rock and a few fish, and the tank has been running for about three months now. I'm currently using a 36" Coralife Aqualight Pro out of my old setup, which has 1x250W HQI lamp, 2x65W CF lamps, and 2x1-watt LEDs. My problem with the new setup is the canopy. I've only got 6" from the top of the acrylic to the bottom of the canopy, which doesn't give me a lot of room. <<Mmm, indeed...and if you are planning to install MH lighting this will be too close and enclosed in my opinion (bulbs will be mere inches from the acrylic)...serious potential for softening the acrylic and causing a catastrophic failure of the tank. I have seen 250w MH lamps placed within 4-inches of ¾” acrylic soften it to the point where a 14”-wide brace would flex with the push of a finger...and these lamps were not “confined” in a canopy. Even if you position the bulbs over the openings on your tank, I think the confines of your very low canopy will hold too much heat. I’m doubtful fans will even be of much help considering the proximity of the bulbs and the containment of the hood>> On top of that, both top sides of the canopy open up independently, so I'm not sure how I could hang a fixture over an opening. <<Not sure I follow this...>> (The openings have acrylic covers, but everything I've read thus far says that the MH lights aren't as efficient shining through the acrylic.) <<Is not a matter of efficiency...”clean” acrylic will allow about 95% light transmission regardless of the light source (and for what it’s worth...regarding reef systems, metal halide gives the most “bang for the buck”...in my opinion). But you don’t want to leave those covers on anyway as they trap heat, reduce evaporative cooling, and, depending on how your system is configured (e.g. - sump/no sump), can prevent adequate gas exchange>> The Coralife light is currently resting on modified legs, with the lights just over 2" away from the top of the acrylic. <<Dangerous...in my opinion>> Any help that you could give me would be greatly appreciated! Great work on the site, and if I left anything out, please let me know. Thanks! Heavy D <<Well Heavy D, your options as I see it are these... You can use the current canopy but with a “cooler running” light source light standard-wattage fluorescent bulbs (will limit stocking organisms with “high” light requirements). These standard-wattage bulbs will still need good ventilation to prevent excessive heat buildup in the canopy. You could consider HO (T5) or VHO fluorescent tubes, but these get “quite hot” and again, the confines of this low built canopy may prove too much... Another option is to abandon this canopy and build/have built one that is “designed” for use with the high-intensity metal halide lighting... A third option is to abandon using a canopy altogether and opt for open suspended lighting such as metal halide pendant fixtures. You don’t state what biotopic representation/type of reef tank you plan to keep...but if you really want to utilize the high heat producing lighting usually associated re...it just doesn’t seem like the canopy you have is going to work with this acrylic tank. Please write back to discuss further if you wish. Regards, EricR>> Re: MH Lighting, Acrylic Tank, Very Low Canopy...Not The Best Recipe - 10/19/07 Thank you for the quick reply. <<Quite welcome>> Your name is a good one, but to set the record straight, it seems that you've spelled it incorrectly. I believe it's spelled with a "K". <<Ha!...perspectives!>> To give you a better idea of what I'm working with, I've enclosed a few pictures. <<Thanks much for this>> Picture 1 is my setup as it sits, without the canopy. <<Okay>> Picture 2 is where my Coralife MH light sits right now, on the modified legs. Not too far above the acrylic... It's 3/4" thick, and I haven't had a problem yet, but I'm pretty sure you have a lot more experience with this kind of thing than I do. <<It may well be fine>> Picture 3 is just an overhead view of the top of the aquarium. <<Mmm, not much “open space” for sure…the bane of the “stock” acrylic tank. Obviously whoever designs these has never had to “work” in one of these tanks…>> I too wish I would have had something a little more "custom" built, as this was a standard Tenecor tank. <<Indeed>> They built the cabinet and the canopy as well. <<I see>> When I ordered it, I didn't really have the intention of building a dedicated reef tank. <<Oh?>> After reading up on the subject and seeing all kinds of pictures, I decided after the fact that it was something I wanted to do. <<Ahhh…the little slice of ocean in your living room… Can be/is very addictive… As said by this 30+ year marine hobbyist who became a “reef-addict” about 17 years ago now…so I do understand the allure>> Probably not the smartest thing, but it is what it is. <<Yup>> The cabinet is too small to house my sump/refugium, (that's all in the crawl space) and the canopy is apparently not tall enough to house MH lights. <<A common problem all around… I do wish manufacturers would design these items with more of an eye toward housing the necessary support systems>> Again, I wish I had something a little different. <<Mmm, how’s that saying go… Hindsight is “always” 20-20…>> As far as the canopy goes, I'd like to use it with my current setup, as taking it off doesn't leave the tank near as aesthetically pleasing. <<Indeed>> It's in a dining /living room area, and I like the way it looks with the canopy on. <<Understandable>> Picture 4 is the canopy, and that's what I meant when I said that both top sides of the canopy open up. That's my only way to get inside the tank, and I don't know how I would suspend something underneath them. Not that 6" gives me any room to suspend something... <<Ugh… I see what you mean. Looks like 36” fluorescent bulbs mounted to each door will be your best option>> When it comes to species, I really haven't decided what I'd like to keep yet. <<This will determine your lighting needs>> Any recommendations that you have would be greatly appreciated. <<I suggest you first research and decide on a specific biotope or niche of the reef you would like to replicate. Stocking organisms from the same ocean and reef habitat/zone/niche can mean much toward long term success>> Again, I don't really want to get rid of the canopy, so if I need a light source that's not going to be bright enough for my setup, I guess I'll have to deal with it. <<If you can get some air flowing through the canopy…T5 HO lighting is worth a try. I doubt you can fit the 4-foot 54w bulbs and end caps on those door panels, so you will have to go with the 3-foot 39w bulbs. I figure you can fit about eight bulbs or more (w/reflectors) per door panel on this 36” deep (wide) tank. The T5s are very nice technology…I have even seen some beautiful European SPS tanks lighted with these bulbs, so…the possibilities/choices for your reef may be broader than you think>> It's been fish only so far, and by the sounds of things, it may have to stay that way. <<Maybe not… I would feel better if the canopy were taller to allow better heat dissipation along with positioning of bulbs (metal halide) further away from the acrylic. But if you can get enough air moving through the canopy through the installation of some fans, the T5 lighting could work out fine>> One more quick question for my current setup... <<Sure>> I've been getting a lot of algae on the front glass. If you look in from the side, you can see that it follows the pattern of where the light shines. <<Typical>> Is this just a case of having the lights on too long during the day? They're on for about 12 hours right now. <<Nope, this lighting period is fine. The algae is likely a result of the newness of this tank (hasn’t found/reached its “balance” yet)>> The light is so bright at night that I've had a few neighbors ask if I currently have a 1.)Botanical garden or 2.)A tanning bed in my living room. <<Hee-hee! When I was building/installing my system (in-wall), and before I had the lighting enclosed, my neighbors and visitors to the house thought I must be growing “Pot” in the living room because the light was so bright!>> Should I cut the lights back to 9 or 10 hours to help with the algae? <<Not my opinion>> I can only assume this will get worse if I add more lights. <<Unless something is amiss with your filtration/feeding/stocking levels, or you’re not filtering your tap water…this will likely pass>> Thanks again! Heavy D (a.k.a. Erik) <<Always welcome…do let me know if I can assist further. Eric Russell>>

Metal Halide Lighting... mostly  10/16/07
Hey,
So I have a few quick questions: I have a 36" 442w metal halide fixture (2-96w blue actinic, 1-250w 15k Halide), and it is leg mounted above my aquarium, ~6" above the water. My tank is a 65 gal tank, 2ft deep and 3ft wide. Should I worry about this being too much light for my corals?
<... depends on what you mean by "corals" and what they've been kept "under"...>
I currently have a waving hand xenia situated about 20" below the halide, a frogspawn in the far corner on the bottom, some green star polyps in the opposite corner of the frogspawn and a few mushrooms about halfway down the rockwork in the middle of the tank. All seem to be doing very well, the mushrooms have almost doubled in size in two weeks, the green stars open daily and the waving hands have 6 new sprouts. The only one that is a little off is the frogspawn, which originally had 3 branches, but the smallest one (which was tiny) seems to have died off, while the other two are looking all right and opening everyday.
<Is something other than lighting at play here...>
Should I worry about the small branch dying off?
<Maybe>
Also, unfortunately, the MH bulb is right above the center brace of the tank.
<I'd move the light slightly to one side or t'other>
I have had it running for over 3 months now, and have seen no signs of melting yet, but have read some horror stories of what can happen when they melt. Should I do anything precautionary for this? I was considering placing a few acrylic braces across the tank evenly spaced, but distanced from the MH bulb. I would probably have to shape them something like this: l__________l but inverted, and make it large enough to slip around the outside rim of the tank, then cement into place. Thanks for this website, I honestly would have probably either given up or wasted alot
<No such word...>
more time and money than I already have without, you guys are great!
Thanks,
Dan
<Mmm, please read here: http://www.wetwebmedia.com/marine/inverts/index.htm
re: Euphylliid Health, Cnidarian Compatibility... Bob Fenner>

Metal Halide Fixture Choices vs. Over-Heating Issues – 08/10/07
I have looked through the articles posted and can't find an answer to my question so here it is. I'm looking for MH for my 240G set up. The tank is 72x30x25. I am planning on 3x250w MH supplemented with T5's.
<<Okay>>
My question is what is the best type of lighting to go for?
<<Mmm...what is it/what effect do you wish to achieve?>>
I'm putting these fixtures in a canopy. I was very keen on the Lumenmax3, but fear they might have a heat build up.
<<This is a very nice reflector/pendant, and no more likely to cause heat problems than any other...and heat “will” be an issue in this canopy regardless of the lighting fixture>>
What I like about them is that they are compact and have the UV glass shield.
<<I can think of some others with the same aspects...but this pendant is a fine choice>>
I have also read reports on the vented Lumenarcs, do you need UV glass under them if they are in a canopy? ( I guess they would still be dangerous when you open the hood).
<<Indeed you do, any time you are using the “double-ended” bulb fixtures...and the hazards of not doing so extend to your livestock as well as to you and your family>>
I have also got a fairly large (1300 cfm) <fan> that I was going to suck hot air out and have fresh air supplied by the A/C ductwork (or outside air in the winter).
<<Sounds like a good plan>>
I'm still a little confused as to what would be the best setup with regards to minimizing heat build up.
<<I think what you have outlined should be fine, though you may have to experiment with the size/number of fans and vents to handle the overheating issues>>
Thanks in advance for your help.
Olly
<<Happy to assist. EricR>>

Re: Metal Halide Fixture Choices vs. Over-Heating Issues - 08/11/07
Thanks I appreciate your reply.
<<Quite welcome>>
What would be the minimum distance from the bottom of the reflector to the water?
<<Whatever places the “bulb” within a general range of about 8” – 12” from the water’s surface>>
I have a 12" canopy, and say the water will be about 1" from the top of the tank, and that most fixtures are between 6" and 8" that will only give me about 5" -7" of clearance. Is that sufficient?
<<Considering the bulb will be a bit higher within the fixture, yes, this will likely be fine>>
Thanks again,
Oliver R Oakley, PhD
<<Happy to help, Eric Russell>>

Glass lid needed with metal halide?  – 07/26/07
I've found so much information searching on your FAQS on the web.
<excellent>
I wasn't able to find a answer with the same equipment as in my tank. I ordered a Sun Pod 2x250w 14k MH fixture for my 90 gallon reef and it will be mounted 12 inches above my glass lid. Since I plan to keep SPS corals in my aquarium, will I need to remove my glass lid in order to give enough light to the corals?
<The glass lid will, to some extent, decrease the amount of light getting to your corals. But how much light it will impede depends a lot on how clean and dry you keep it. Lids have a way of getting wet, salty, and/or dirty pretty fast.>
As for the heat issue, I have a chiller set at 76 degrees.
<You'll definitely need that chiller with the glass lids and metal halides.>
Which can be adjusted as needed when the fixture arrives so I don't think I would need to remove the glass lid for the heat issue. If you guys/gals think I should remove my glass lid, I'm very worried about my fish jumping out. Any way to prevent this?
<Since you have a chiller, the only concerns left with the lids are going to be of gas exchange and the lids getting wet, salt, and/or dirty. If you can manage to get good aeration even with the lids, and if you can keep the lids clean and dry, then you should be ok. But if all that becomes too difficult, there are a few other ways of keeping fish from jumping out. If the fish aren't really small, eggcrate should work. If not eggcrate, there are other similar type plastic grates you can get at hardware stores that might work.>
Thanks so much again for all of your support!
<No problem>
Peter
<Best,
Sara>

Lighting/Heating Question (MH lighting and hot temps) - 6/1/07
Hi Crew!
<Hey WS.>
I've searched your site and can't find the help I'm looking for...so I decided to write you instead.
<Okay.>
First off...you guys/gals have helped me tremendously every step of the way from my first 55gal to my current setup 210gal system.
<Awesome.>
My family and friends love our aquarium. My family rarely watches TV anymore. Good thing we didn't get the plasma screen TV instead.
<Oh don't tell anyone I got both...lol.>
Here's my setup...
210 gal, going to be mixed reef system. 250lbs LR
Current livestock is...
9" Volitans Lionfish
1" Yellowtail Damsel
4" Emperor Angel
5" Harlequin Tusk
4" Sohal Tang
1 Devils hand Leather
1 Colt Coral
Large Zoo colony
1 Open Brain Coral
All are doing great!
<Cool.>
I currently use an Aquamedic Oceanlight T5/MH combo. 3x250 watt MH, and 4x39watt T5 actinics. This is a relatively new light (1 month), and I'm having trouble maintaining a steady temp. I run the T5's for 12 hrs, the middle 1x250 watt MH for 8 hrs,
<Too long for the MH, you really don't need much longer than 3 or 4 hours, especially for what you have.>
and the outer 2x250 watt MH for 4 hrs.
<That is okay.>
I don't want to get a chiller (my electric bill is too high already), and I'm just not eager to part with my money.
<I understand.>
With this lighting schedule my temp in the morning is 79.5-80 degrees, and by 2pm it's 80.5 - 81 degrees. I haven't been able to run my outer 2MH's for the full 4 hrs (from 12 - 4pm) that I wanted due to the temp increase. I usually end up shutting them off after about 2hrs of use (which I don't mind doing).
<What about cheap'o computer fans on a timer, can help tremendously and is very cheap.>
I planned on getting 2-3 pc.s of LPSs or SPS (not sure what kinds, still researching). I know my livestock might not be reef safe, but so far so good.
<As long as you know the risks.>
Finally, my question...
<Okay.>
Since my 1x250watt MH is on for 8hrs, do you think these corals will do well under the lit part of tank? I was thinking frogspawn, Montipora Plate Coral, and maybe an Acropora frag?
<Zooxanthellae hosting organisms really only need 3-4 hours of direct (MH) lighting, the rest can be supplemental fluorescent lighting (The T-5's).>
Thanks again.
<Anytime.>
WS
<Adam J.>

Re: Lighting/Heating Question (MH lighting and hot temps)  - 6/7/07
Thanks Adam
<Anytime.>
Is it harmful to corals soft and hard, to have the MH on for 8 hrs?
<I wouldn't leave all of them on that long but if you want to leave the lower wattage, center one, out of three on for an extended period...and I assume this is for aesthetics...ten I don't see an issue. Keep in mind though that it may/will contribute to algae growth.>
I like the difference in colors with the T5's on and 1 MH on. It looks
cool.
<I bet.>
Thanks again.
<Anytime.>
Wayne
<AJ.>

MH Distance from the water?   3/21/07
<Greetings!  Mich here.>
I have an Outer Orbit all-in-one system. 550 Watts. 2- 150 Watt 10K metal Halide, 4 54 Watt Actinics, and lunars. How many inches should it be from the water to get proper lighting, but minimize evaporation and heat?
<Generally 4-12 inches, in you case, 8-10 inches would probably be best.>
Thanks.
<Welcome.  -Mich>
PS - I do not run the Halide's all day to save electric cost.  
<Hopefully is at least 8 hours, 12 would be better.>

Lighting...Metal Halide Placement 1/9/07
I own a 180 gallon tank with a retrofit kit attached to the canopy hood cover. That light has 3 -250 watt 15k bulbs and 2 VHO bulbs. I also have 2 VHO lamps near the water, not attached to the canopy. The light looks fine but when I take pictures their not as good as the LFS's  tank when I take photos of theirs, and they have a 180 gallon also with the same kind of light wattage but no canopy and their lights sit 7 inches above the water. My question is what is the appropriate height for metal halides with a wooden canopy. I think it said  9-11 inches on your site I believe, but did not say if it was with a canopy. what should I do? If it's too close will it boil the tank. What's the right height for intensity and not boiling the tank?
<Harry, the canopy lights should be fine providing you have a large enough (cfm) fan to exhaust the heat emitted from them.  The hood will require an inlet and outlet for the fan to operate properly.  As for the VHO's, why run them?  Your halide system alone is more than enough for your tank.  The photo problem;
I'll bet the Kelvin temperature is different on the LFS lamps than is yours.
His indirect lighting may be much brighter also.  If your camera has the capability to select white balance, change this to the different settings available, and I think you will find something to your liking here.  Experiment with it.>
Harry
<James (Salty Dog)>

Metal Halide Bulb Placement (Parallel? or Perpendicular?) - 04/30/06
Hello wet web,
<<Hiya Mike!>>
Let me lay out what system I have really quick to give you a better idea of what we are working with.
<<Thank you>>
I have a 100 gallon SeaClear System-II aquarium.  One main pump, two powerheads and a separate pump for the chiller.  2x175watt MH and a 1/4 JBJ Arctica chiller.  I have read through your FAQ's but have not gotten a definite answer.
<<Ok>>
My question is, is a 2-degree temperature fluctuation too much for my fish and coral?
<<Not usually, no>>
The chiller cools from 78.5 to 76.5 in about 20-25min and it will do this about 2-3 times per day depending on how hot the day is.
<<Mmm...that's a pretty rapid drop>>
Is this how this chiller is supposed to work?
<<Yep>>
If not, what is an acceptable range for a chiller to chill?
<<?>>
Do I have the settings on wrong?
<<Not "wrong" per se, but could be "improved".  Does your chiller allow you to adjust the temperature differential?  You should be able to set the differential (the number of "degrees" the water temp is allowed to rise from your "set" temperature before the chiller kicks on), adjust this to 1-degree of differential to reduce the size of the temperature drop>>
I have the low setting at 76.5 and the high setting at 78.5 degrees.
<<Ahh!>>
What am I doing wrong?
<<Nothing really, all is probably fine unless you are seeing signs of stress in your tank inhabitants.  But for a more "stable" environment, you can either increase your "low" setting or decrease your "high" setting>>
Also, does it matter if I mount my Halides perpendicular or parallel to the front of my tank?
<<Most folks opt for "parallel", but if you have adequate light spread/coverage I don't see what difference it really makes>>
Keep in mind that I have a rectangular 5' acrylic tank.
<<I too have an acrylic tank...my halides are mounted parallel>>
I was thinking of using the PFO parallel reflector that can
also hold two power compacts or I can also use the PFO parabolic reflector which places the bulbs perpendicular to the front of the tank.  Do you guys know if these reflectors are any good?
<<I use PFO reflectors, I think they are a fine product/value>>
The reason I'm asking is because I heard that if you place Halides perpendicular to the front of a tank it can warp the front of it.
<<Huh?! How?>>
Is this true?
<<Not that I've ever heard>>
What can happen to my tank?
<<Whether your bulbs are positioned parallel or perpendicular should make no difference in this respect>>
The help is much appreciated,
Mike
<<Mike, considering the dimensions of your tank I think a parallel configuration would be optimal...but if you' rather go perpendicular I don't see any great problems with this either.  Regards, Eric Russell>>

90 gallon Reef MH question, heat   9/5/06
Bob,
    I have read a lot of your articles on WWM about the  Metal Halides and everything else.  I currently have a 90 gallon all glass  aquarium with a corner overflow.  I'm currently using a Aqualight Plus  Fixture contain 2 10k whites and 2 actinics all being 96 watts with the standard  wooden canopy above the lighting and the tank.  The tank without the use of  a heater stays around 77-78 degrees.  I'm playing with the idea of getting  the New Outer Orbit lighting system that contains 2 150w 10k  HQI MH and 2  130 watt PC Actinics.  With the tank being a taller tank and liking the  shimmering effect of the MH i wanted to know if there was a way to include the  canopy at least on the outside without worrying about the heat issue.
<Fans... a chiller...>
I  don't mind having an open top canopy but i would like to at least have some type  of a canopy so that i don't see the light fixture.  I was thinking about  installing two fans in the back on the canopy to blow the air out from under the  lights as well as drilling some holes on the outside of the canopy to allow air  flow thru the fixture itself that does contain an 3.5 inch fan always.
<Better to blow in and out...>
  I  just don't really like the fact going somewhere and seeing the lighting fixture  and the light peeking thru the sides between the light and the top of the  canopy, but i do understand that MH put out a lot of heat but i wasn't sure if  these HQI lights with the new design of ballast put out else heat.  But my  main issues is being able to put the light system on the tank without it being  too much light for the corals, LPS, Calms, SPS and zoos and polyps.
<Won't be here>
  And  having some type of a canopy around the sides so the tank looks complete like a  piece of furniture not just a tank
please let me know
Thank you
Drew
<Can be done... will likely need a chiller. Bob Fenner>

Re: 90 gallon Reef MH question.  9/6/06
With the MH being about 7 to 8 inches off of the water is this ok, or is it going to cause the light to be too intense for the tank.
<Need to elevate this high or higher for light distribution and safety reasons... see the manufacturer's recommendations re>
  Do you believe that with fans I can keep it cool or more than likely i will have to have a chiller, which i really don't want to purchase at all.
Drew
<More than likely the chiller will be needed if using 250 watt units or higher. Bob Fenner>

T5 or MH, Heat Issue...   9/2/06
Hello Crew,
    I'm upgrading my 100 gallon tank into a reef tank. Currently I'm planning on removing my closed canopy and replacing it with an open lighting fixture. I've set my mind on either Metal Halide or HO fluorescent T5 lighting.
    The thing is, I don't know which lighting will be better for my setup.
My tank dimensions are 58" wide and 18" deep. I would like to keep Bubble-Tipped Anemones and Tridacnid Clams (I would place the clam at the bottom of the tank). My preference in Corals is still not clear, but I would like to be open to a wide range of possibilities.
    I've read through your FAQs that Clams prefer MH (and so do I, due to the pleasing shimmering effect), but heat is an issue to me. My room temperature is 25 C, but my tank is around 27 C and I think it's mainly due to the trapped heat in the closed canopy (with three 40 watt fluorescent lamps, will remove soon). I'm also adding more powerful powerheads that will add up to the heat. I'm not sure if T5's will provide enough lighting for the intended inhabitants while emitting low heat, and need your inquiry.
Thank you. Have a nice day.
Mohammad
<<Mohammad:  While there are some people who like T5's the vast majority of people that have anemones and clams (including me) have MH lighting.  If your canopy is open, I don't thing the MH lighting will significantly increase your temperature.  Some day, we may be able to light our tanks with LED's; but, the technology is still being tested.  Best of luck, Roy>>

Cube? MH, heat concern 7/16/05
I'm planning a  26"X26"X23"  tank.  My wish is for single 150 watt HQI  to support a FOWLR  system.  The internal overflow box spans the back, has three 1" bulkheads,  and  two pairs of  3/4" , on the bottom of the tank.  (Two for return, and two for a possible future closed loop.)
<The return/lines you may well want to raise up to prevent back-siphoning in the event of a power/pump failure>
The Iwaki MD-40RX, for a SCWD only return,  The sump's water depth will be below  9" to accommodate a Aqua-C EV-120,  and incorporates a  25 gallon refugium.   I would appreciate any advice, or to know if I'm on the right track, here in Taiwan.  Thank you, for your invaluable service.  I apologize if I have been unclear.
-Ryan
<You may have heat issues with the size, shape of the main tank, volume of water. Bob Fenner>

Too much light? MHs 8/9/05
Hello crew,
I have a 125g (72Lx18Wx22H) salt water tank w/fish only.
I plan on a reef tank w/light loving corals. I bought a used dual 400w MH kit at a great price. I know this is too many watts for the depth of the tank, but I couldn't resist for the price. So can you please tell me what I can do to make it work. I read that you can use window screen in layers but wouldn't this melt?
<If it's too close, yes>
Can I move the lights higher than normal?
<Yes>
The tank has two plastic braces at the top, how hot will these get, and can I cover them with a heat shield type of cover. Thank you for any info.  
<No heat shield... but you want to keep at least a foot of space between, and never heat them more than you can stand to place your hand on... You might look into means to "turn down" (through electronics) your 400 watt units to lower wattage (will save you a bundle on electricity costs, as well as not having to walk around the house with sunglasses on...). Contact the larger lighting outfits... maybe Perry Tishgart at Champion... re this possibility. Bob Fenner>

Metal Halide (UV) Shielding - 10/13/05
Hello all and thanks ahead of time,
<<Howdy>>
Am somewhat confused at why MH spotlight type pendants are able to be shielded in pendant and HQI fixtures are able to be shielded in pendant, but MH hoods and canopy lights cannot except for a lid on top of aquarium at some distance from bulb.
<<Not sure where you got this info, but most any manufactured light fixture, whether pendant or otherwise, mogul or DE, will come with some type (plastic/glass) lens (shield) attached to the fixture. I wonder if you might be referring to the argument on "whether or not" to shield MH bulbs? There has been some debate on this, and many folks choose to shield HQI/DE bulbs because they lack the outer glass envelope of a mogul bulb. You can argue that the sun has no such shield, and there are writings stating that much of the colorful pigments seen in some corals are proteins produced to "shield" the corals from the sun's UV...but most folks will err on the side of caution and shield their HQI/DE MH bulbs. I currently utilize mogul bulbs, and I don't shield them.>>
Are HQI / mogul type spot pendants and fixtures less hot than canopy / hood MH lights?
<<Not as a rule...depends on design, wattage, presence of electric fans...>>
Just finished Mr. Calfo's Book of Coral Propagation. Rarely is a book so informative and fun/entertaining at the same time!!!
<<am much in agreement>>
Bravo A.C. and thank you all,
Peter
Puzzled in Lakewood, Ca
<<Regards, EricR>>

Re: Metal Halide (UV) Shielding - Follow-up 10/15/05
Thanks Eric!!!
<<Most welcome>>
To follow up then, the MH mogul type aluminum hoods with a fan on each end can be shielded right there on the hood, similar to a fluorescent fixture?
<<Sure...will likely come with some type of splash guard which also functions as a UV shield. Some materials (treated) are better than others, but any glass or plastic lens/splash guard will filter "some" UV.>>
If so then is it placed directly on tank top, suspended, mounted or any of the above?
<<Is up to you...but I don't recommend placing (resting) the light fixture directly on the tank top. Allow a couple inches for air circulation...some fixtures come with little "feet" for this purpose.>>
And for retro fixtures attached to wooden canopy top, can the bulb be shielded at the fixture instead of having to cover the tank with a sheet of glass/acrylic?
<<This can be done by attaching to the hood, yes. But if you go with mogul bulbs I don't see the need myself.>>
I've never seen moguls shielded in a retro fixture for some reason. I am a safety consultant by profession and it makes me cringe to see those exposed bare bulbs above the water. It gives me a "0" comfort level.
<<Little to be concerned with here, really...the mogul bulbs are already shielded by the outer glass envelope. The biggest danger in my opinion is breakage caused by splash on the bulb, and even this is minimal. Most folks are trying to get all they can out of their lighting, and adding a "shield" only reduces intensity/PAR.>>
Just like all the tanks I see set up relying on check valves to prevent back siphoning. Arggggh! Or single hole overflows!!! etc.
<<agreed>>
Please indulge my "safety first" nature with my above concerns regarding the MH's.
<<No worries mate, you have to do what makes you comfortable. You can still provide adequate lighting for your wet pets with a little planning.>>
THANK YOU and BE SAFE
Peter
Lakewood, Ca
<<Always welcome, EricR>>

More On MH Lighting Shielding - 11/18/05
Thanks Eric!! Getting clearer. One more follow though, please.
I have read on your site that by mounting MH too close to the tank top this has caused the glass to crack/acrylic to melt.  If true, what material is used to shield bulbs in fixtures (like HQIs for instance that does not crack/melt so close to bulb??
<<Tempered/treated glass...adequate air flow around same.>>
And why does tank brace crack, but not shield glass?
<<Not usually tempered/treated to withstand extreme heat.  Keep in mind too, the glass used to shield the bulbs is not under the same stresses the tank brace is (i.e. - bracing together a tank full of heavy water).  As for plastic, some of the bell-type pendants use plastic/acrylic shields.  These don't "melt" due to the air flow around the fixture, but, place it too close to the tank top and restrict that air flow...you get the picture.  Ideally, you won't have a cover on the tank (reef tanks especially, need to "breathe"), and most fixtures with multiple bulbs are designed to place them on either side of a center-braced tank.>>
Sorry for follow ups, just want to be clear on this.
Thank you
Peter
<<Follow-ups are no problem my friend, EricR>>

Aquatinics MH Hoods - 10/15/05
Hi Eric,
PS--please check this Aquactinics.com site for MH hoods that can be set right on top of tank and contribute almost zero heat. What do you think, please?
Skeptical but intrigued in Lakewood
Peter
<<Mmm, might be fine but like you...am skeptical. I would still conspire to raise the fixture by an inch or two...perhaps fashion some "legs" from acrylic for this purpose. I'm guessing you noticed the UV splash shield? <G> EricR>>

MH light height  1/8/06
Hello all,  
<Hello.>
I hope the holiday treated you all fine !
<No complaints here, thank you for asking.>
Just a quickie,
<Sure.>
have a 55 Gal Mixed salt water tank that’s around 20in Deep from water surface to sand bed,  I have 2x250w 14,000k Halides running 10hrs and 2xActinic running 12hrs.  The lights themselves are rated for a tank up to 36in deep and the manufacturer recommends a minimum distance of 8in from the waters surface, however the lights are causing a temperature fluctuation of around 4 deg (79 to 83 deg) over the 10hrs.
<That’s not cool.>
Due to the main tank being located in our family room I am unwilling to have a noisy fan running for 8hrs a day at this time and a chiller isn’t an option.
<X2, 3” computer fans won’t, can’t, even be heard over the noise of the average aquarium pump.>
  With the lights being really more powerful than the depth of tank I have require at this time.  
Would increasing the distance to around 12-15in to lower the heat transfer from light to water, have adverse effects on my Clams & softies (leathers, mushrooms, Xenia).
<This distance (height) should be fine for your tank.>
Happy new Year to you all from Wiltshire in the UK.
<And a happy new year from SoCal, Adam J.>

MH v Fluorescents, power consumption   1/10/06
Hi WWM Crew, <Hello Steve>
I was reading one of the FAQ's when I came across a minor mistake and thought I would correct it. The WWM crew was asked if 150 watts of MH consumed the same amount of power as 150 watts of fluorescents and the answer was yes a watt equals a watt which is true but watts = amps x volts and a 150 watt MH light will consume more power or energy whilst supplying the same amount of watts, i.e.. more amps. The extra power is dissipated as heat from the ballast.
<This particular answer may be dated.  The efficiency (power factor) of a system depends on the ballast.  Electronically regulated ballasts will be more efficient than a tar ballast and so on. This will also relate to light intensity somewhat.  On a 48" tank, two 150 watt HQI's are going to be more effective than 400 watts of fluorescents and generate less heat into the tank.  So now we are looking at light intensity versus wattage being used.  More than just watt for watt has to be considered here.>
I hope this helps, regards, Steve. <I hope this helps also. James (Salty Dog)>

HQI bulb   1/18/06
Hello, <Hello Orestes> I am starting a 60 gallon reef tank and have a retrofit kit for two 65 watt actinics and 1 150 watt HQI double ended bulb. The lights sit about 5 inches from the surface of the water and my question is how should I place the bulbs so that I do not have any problems with the heat of the HQI affecting the actinics. Oh, I also have two 3" fans from Coralife one blowing cool air in and the other sucking hot air out. <The heat from the HQI will have no effect on the PC's.  James (Salty Dog)> <<I have a differing opinion. Would situate the fluorescents at a distance that is comfortable to your touch... RMF>>
Thank You. <You're welcome>
Orestes

Halides?
Hello, I've reading you site and it is great!
     I have a 55 gallon aquarium.  Currently I have a Tunze pump that has the flow restrictor pointing to the surface.  There is quite a bit of surface agitation which is preventing the power compacts from penetrating too far into the aquarium.  I know because when I turn it off it becomes quite a bit brighter in the aquarium.  So, I am thinking about purchasing two 175 W metal Halides and installing fans in the canopy.  << Excellent idea. >> I live in San Francisco where it is cool most of the time but in the summer in can become hot enough to be a problem. << My diving partner lives in San Francisco. >> Do I need a chiller? << Nope, a few fans and opening the back of the canopy will do it.  Having air conditioning in your house is also very helpful. >> Also, are metal halides the way to go.  I currently have some brain corals and clams and would like to grow SPS corals. << Without a doubt.  I would definitely go that route.  >>
Thanks,
-Brent
<<  Blundell  >>

Lighting...
Hi...I have a 48in. X 18in. X 18in. reef aquarium. I am using 4 fluorescent lights. I am thinking of using metal halides. If I were to use metal halides, must I use a chiller,,,?? My aquarium is between 29 - 27 degree Celsius with 3 fans on. Without the fan, it will be around 30 - 32 degree Celsius...when using metal halides, how high should I place it above the water surface (planning to use a 150 watt metal halides)...??
Thanks...
>>>I don't use a chiller, but every tank/room combination is different. With 150 watt halides, you should be fine without a chiller though. Keep the fixture 35cm above the water or so.
Cheers
Jim<<<

Lighting... dangers of MH use
Good evening.  I have looked on the wetwebmedia website and have found some information on this topic but not any detailed discussion.  I have a tank that is 120 gallons (4 feet x 2 feet x 2 feet).  I have an enclosed wood canopy with HQI metal halide lights (2x250) in housings with clear acrylic (glass? not sure which, they are the standard HQI housings and covers that are rectangular) covers and two power compact actinic bulbs without shielding.  
To reduce the heat in the tank I usually use two small half inch blocks to slightly raise the top of the canopy so that there is a gap for air to escape.
<Mmm, would be better to drill some ports... chimneys if you will for passive venting... better still to blow air in/out via fans>
  The tank is kept in our living room with the lights running for approximately 9.5 hours per day.  I also have a young child.  My question is regarding any danger that is posed from the metal halides and, in particular, UV-radiation.
<Modern aquarium metal halides present little danger from UV>
Am I potentially introducing a health risk into our home, particularly in terms of having a young child in the house?  Any input on this would be much appreciated.  I have seen some articles on this topic but no definitive conclusions.
Thanks.
- Brian
<I do share your concern... particularly re heat issues, the possibility (very real) of fire. Do please look into drilling those vent holes and the possibility of adding fans... check that acrylic anywhere near these lamps is not discoloring, crazing from heat... the flashpoint of this material is not far from this... Bob Fenner>

Re: MH Lighting danger
Thanks very much for the response.  One important item I forgot to mention is that I prop the canopy in the front by a half inch because I have two four inch fans on the back of the tank that draw air into the tank and the gap allows the air to escape in the front, thus keeping the lights cooler.
<Ahh... better to just cut some holes (like with a hole-saw and a drill motor) and affix some screens over... for intakes>
Anyway, my primary concern was if the metal halides pose any health threats, particularly to very young children.  I was particularly concerned with UV and if there are any other concerns.  I had mentioned the propping of the lid because this lets a little bit of additional light into the room.
Thanks.
- Birna
<Yes, I understood, understand the UV to be the primary concern. To be more specific, for the sake of concern re ultraviolet damage to eyes, modern fixtures (all supplied sans such filters) do NOT pose a threat... and older ones will come supplied with such transparent screens. Modern MH/HQI lamps have such radiation shielding built in to their construction/glass. Bob Fenner>

Re: MH Lighting danger, fans
Great.  So it sounds like my fear of medical damage from UV appears to be unwarranted with the modern fixtures/bulbs (be they vision damage, developmental damage, health risk, etc.).  I guess if there was a risk they would not be selling these items(?).
<Mmm, I would NOT go this far>
Sorry, last question on the fans.  Do you think that I can move the fans to the front of the canopy with some spacers between the fans and the wood and then close the front of the canopy (basically blowing the air out the back), or would this likely not work since I would not be drawing in any cooler air?
<I would NOT place the fans or vents in the front... annoying light, sound... affix them to the back, sides, top... Bob Fenner>
Thanks.
- Brian

Re: MH Lighting
Thanks very much for your advice and for the great website; it has provided me with invaluable assistance in choosing appropriate aquarium inhabitants.
I guess I was pushing it a bit in my assumption on the ethical composition of the lighting industry, but it sounds like the health risk that I was concerned with for the metal halide lighting is not existent.  That is a relief.  On a side note, I took a closer look at my lights and the covers on my halides are glass and not acrylic.
Thanks again.
- Brian
<... the glass will filter the UV. Have you read the collective FAQs on Metal Halide use on marine aquariums? Here: http://www.wetwebmedia.com/marine/setup/lighting/mhmarfaqs.htm
and the links above.
Bob Fenner>

Halide upgrade and center brace
Dear Crew
I have read somewhere on your website that its dangerous to have halides on an aquarium with a centre brace? My tank is a 72 inch x18 x 24 high. I am upgrading my VHOs to an arcadia pendant style MH setup (series 3). There will be a new open top hood placed on the top of the tank. My question is why is there a problem with halides and a centre brace? 
<Jim, I think what is implied here is that a halide directly over the center brace (most braces are plastic) will cause the brace to soften and allow the tank to bow. If you are going to use just two 250/400 watt (whatever) halides adjacent to the brace, with plenty of air movement, you probably wouldn't have a problem. James (Salty Dog)>

Hey, It's Gettin' HOT in Here! Lighting/Metal Halide
To the crew, Hello and thank you for taking the time to answer my questions. First I would like to know if, in your opinion, two 175 watt metal halides would be adequate to light a lagoonal-type SPS dominated 46 gallon bowfront aquarium? The lights are just about 8 inches above the water surface. This leads me to my second question, with the lights being so close and the tank located in an alcove, the water temperature reaches 83 degrees, what is too high for SPS corals? I realize that there is no one set temperature but I am concerned that when the corals are eventually added this temperature will be a problem. Lastly, as I do not have a chiller and will not be able to purchase one immediately, I have an idea to use a dryer vent system and vent the excess heat away from the tank, do you feel this would help to control the temperature a bit. Thank you again. 
<Yes, it would as long as the vent system is powered by a fan, I believe that is what you meant. James (Salty Dog)> 

Hey, It's Gettin' HOT in Here! Lighting/Metal Halide Follow-up
James, Thank you for the quick reply. To clarify my idea I will use the fan on the halide hood to move the heat from the bulbs through aluminum vent material into another room. Do you think this is a workable plan? It's better if you can pull the air through the vent rather than push it. Sounds workable to me.> I would also like your opinion on the use of two 175 watt metal halide bulbs on a 46 gallon bowfront, the dimensions of which are 36 inches long with a depth of 18 inches. I would like to stock the tank with lagoonal-type SPS in the upper half of the tank and slightly lower light SPS below. The bulbs are about 9 inches from the water surface. I will be using two XM 10K bulbs with actinic supplementation. Assuming proper water chemistry, will these two bulbs be able to provide the proper light for the corals? 
<Most definitely. Matt, next time you reply, do it on the original message as we get plenty of mail and when we get a return such as yours, it's hard to remember what was originally said. It helps to be able to reference the original query. Thanks. James (Salty Dog)>
Thanks again, Matt 
<You're welcome>

Metal Halides over Acrylic
Good Afternoon/Morning crew at Wetwebmedia,
<Good morrow to you>
I have a question on Metal Halide lighting and I was wondering if I can pick your brains one more time. :)
I currently have a 157 gallon acrylic tank( height is 29 inches and 18 inches wide). It's been up and running with 3 VHO bulbs (420 watt) for 2 1/2 years now and houses mostly soft corals (leathers, polyps, pagoda cups, Xenias etc..25 total) I've been thinking of upgrading my lights to metal Halides so I can put in some clams + SPS corals. However, I am concerned that since my canopy is for standard fluorescent lights - approx. 7-8 inches tall (not the super tall canopy for halides), if I could get a way by keeping the 2 VHO lights and by installing 1 or possibly 2 150 Watt low profile Ocean Light HQI halides (saw some at Dr.FosterSmith)?
<You are wise to be concerned here... MH's are hot, the flashpoint for acrylic low>
My main concern is whether the
halides (1 or 2) would affect the acrylic. There are 2 struts with 3 openings. If I placed the halides directly over the openings, not above the struts, would I be able to install them and enjoy some relative peace of mind (assuming they won't crack the acrylic or cause it to craze)?
<Maybe>
The Ocean Light HQI halides are 2 1/2 inches tall so they'd be roughly at the same height my VHOs are currently at (approx. 8-10 inches from the surface water.)
What should be the minimum distance from the acrylic for 1 or 2 150 watt halides?
<I'd consult with the manufacturer re this>
I am planning to have a fan blowing either across or at the water to control rising temps.
<Will help>
Any ideas if this scenario is safe? Are halides safe over acrylic as long as they're not placed directly above the strut braces?
Your input is as always invaluable...
<I give you good odds of not having trouble here... considering the distance, over water, the wattage, use of fans... Bob Fenner>
Thank you very much in advance...
Dimitris

Lighting Quandary...Part II
Okay, one follow up question then.  I have a canopy on my 55 gallon tank and my wife and I both really like the way this looks.  If I were to go to a pendant system, can I mount them in a canopy?
<If there is enough clearance and sufficient ventilation and fan cooling, you can definitely do this. I have pendants mounted in the canopy over my reef system.>
Will I need to worry about temp under my canopy and possible overheating.  (I may already have a problem since my current temp.s in the summer for Freshwater run in the low 80s for about 3 months.  I'm looking into fans to see if that will cool the water enough to get it back down to about 79 degrees.).  What do you think?
<Well, cooling and ventilation are huge issues when mounting pendants in the canopy. My canopy was designed specifically for pendants; you may need to see if yours will work. You should allow at least 6-8 inches of clearance above the water, and a little more room for ventilation.>
Thanks again for your input and support of all of us that are trying our best to learn what we need to keep these beautiful and fragile creatures in our homes and under the best possible conditions!
Jeff Smith
<Glad to be of service, Jeff! Good luck! Regards, Scott F.>

Fluorescent to MH blues... too much heat, vacillation in temperature in a SW 55
Hello all,
I just purchased a new light for my 55 gallon reef tank. I went from a compact fluorescent which was about 130watts total to a metal halide system. I wanted to be able to get some of the cool corals. I already have a few corals and they seemed to be doing alright with the other light but figured they would love the new light. The new light is a Current USA Outer Orbit fixture 48”. It has 1x150W 10K HQI-MH 1/ 2x130W Dual Actinic & 6 Lunar Lights. I Have it mounted almost 13” over the tank. The problem that I’m having is that the temperature in my tank has sky rocketed. It’s usually 76-78 and since I have added the light it’s gone up to 86 which I know is on the high end. The fish and the corals seem to be doing alright but I don’t know what the long term effect will be. I keep the AC in the house set at 70 and I still can’t get the temperature down below 81. When the light comes on the temperature climbs to 86 before the light goes out. Is the light too much for a 55 gallon tank?
<As it is, yes... you have too much thermal fluctuation for health and safety's sakes>
I’ve looked into chillers and they're so expensive. The light cost a fortune. Is there anything that I can do to get the temperature down?
<A few things... evaporative cooling by supplying fan/s to blow air across the surface would help... elevating the light even more over the tank... adding more volume... in a BIG sump/refugium elsewhere, that's tied in with the 55...>
What’s the long term effect?
<Shortened life-spans for your livestock, big electrical bills... all that goes along with these>
Set up is a 55 gallon tank set up in December 2004.
Filtration - Eheim Professional II Canister filter up to 92 gallons.
Protein Skimmer - Aqua C Remora with Mag Drive
Power heads - 2-600, 1 1200 Maxi Jet, 1 Zoo Med Power sweep 228
Heating System - Hydor Eth 300 External Thermal heater
75 pounds of Fiji Live Rock,
60 LBS of Fiji Pink Aragonite Live Sand.
Kent Marine Maxxima 35 Hi-S R/O / Deionizer 4 Stage Reverse Osmosis Unit.
Current USA Outer Orbit Fixture – 48” 1x150W 10K HQI-MH 1/ 2x130W Dual Actinic & 6 Lunar Lights
Inhabitants –
1. Purple Tang
1. Blue Damsel
1. True & 1 False Percula
1. Lawnmower Blenny
1. Dottyback Fridmani
1. Diamond Goby
1. Branch Coral - Paralemnalia or Lemnalia Tree Corals, Finger Leather, Branch, or Cauliflower Corals
1. Red Feather Star
1. Torch Coral – (Brown) Large Polyp Stony
1. Red Star Fish
Misc. Hermit Crabs
Misc. Snails
<Bob Fenner>