MHMarFAQ5

FAQs about Metal Halide & Halogen Lights and Lighting for Marine Systems 5

"Better safe than sorry". Double your supports of light fixtures, particularly MH... Here's Barry Neigut of ClamsDirect using doubled, double panduits/zip-ties to hold up hot fixtures, lest one set fail... disastrously.

Metal halide lighting 07/01/05 I have a 10 K 175 watt metal halide light system and was wondering if I should have glass tank lids on? <Yes, need to filter out the UV. James (Salty Dog)> <<Mmm, actually, many MH lamps come made with their glass acting as such filters. RMF>> Metal halide ballast 30 Jun 2005 I was thinking about purchasing a second hand metal halide retrofit kit. It is a 2x250 watt kit with Iwasaki 6500K bulbs. At the LFS they said it would need new bulbs in a couple of months. However, they said that the ballast would only fire 6500K bulbs. I have never heard of this before, should I be safe and order the same bulbs or could I try a 10K. <Eric, the color temperature has nothing to do with whether the ballast will fire the bulb or not. I've never seen a ballast labeled "For 6500K only", or vice versa. James (Salty Dog)> Thanks for your time and help, <You're welcome> Eric

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>

MH bulb replacement Hello and thanks again for all you do. Your website has been so helpful. I bought a used MH retrofit on eBay about 8 months ago. It was used for 6 months prior according to the seller. I'm looking to replace my bulbs but don't know what type of ballast I have. It is 2 x 175w. Attempts to contact the seller have been unsuccessful. I have been very happy with the light so far. So how I determine what type of ballast I have so I can replace the bulbs? My tank is only 55 gallon long. I built a canopy which is suspended from my ceiling. One bulbs is 20k bulb, one is 13k. Also I have 4x 55w PC fixture in place (2 10k, 2 03 actinic) I installed 3 cooling fans as well in the canopy to reduce the heat you can imagine is generated and temp is always below 80. Inhabitants are various LPS, SPS, soft corals, anemone, mushrooms etc. I would also like to keep some tridacnids in the future. In your opinion what would be a better combo....2 x 175 MH 10ks with 4 x 55 PC all actinic; or 2 x 175 MH 20ks with 2 55w PC 10ks and 2 55w actinics? I know a lot is just personal preference and I do like a "bluer tank", just wanted a professional opinion. <Corey, if you like the bluer tank, then I would go with your last scenario. James (Salty Dog)> Thanks, Corey

MH light bulb Hi everybody. <Hello Nick.> I bought a 400w metal halide hanging pendant light on eBay for $58.00 with shipping on eBay if others need cheap MH lights. These lights were hanging in peoples warehouses and they sell them cheap! So my question is , what kind of bulb do I get for it? I know I need the mogul base and I know I need between 10-20k of color. But I have found bulbs in the shape of a pear, and bulbs that are long and skinny. I have a 60 gallon corner tank and it is 24 inches tall so I know the pendant bulb is ok for this application. So do I need the skinny bulbs or the pear shaped ones? Thanks for the help and keep up the good work! <Nick, in the future please cap all your "i's". It saves us work as we have to edit these queries for posting. I would go with the pear shaped light. The skinny ones are designed for horizontal use. A 12 to 20K would be good. If you like more blue, go the higher K route. James (Salty Dog)> nick 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.>

Lighting Decisions (Pt. 2) Would I need to supplement an HQI system with actinics or would 2 150 watt HQI without actinics be sufficient? <You would only need to supplement the halides with actinic if the bulb's aesthetics do not please you. For example, a lot of people feel that the popular 10,000k halides are too "yellow" for their taste, so they supplement them with actinic. There is no tremendous advantage in doing so other than aesthetics, however, IMO. Many hobbyists like to use actinics to simulate a "dawn" or "dusk" phase before/after their halides go on or off. Again, purely a judgment call on your part.> Also on hellolights.com, it says that a UV glass shield is necessary to protect the life within the tank. I have a glass canopy right now, is that enough? Thanks again! -Ron <The fine folks at hellolights.com (a great company to do business with, BTW) are correct. Double-ended (HQI) bulbs do not have a "shield" like mogul-base halide bulbs do. Pretty much every double-ended pendant that is available in the hobby has the tempered glass shield built in, however, so if you intend to use these bulbs, you'll generally be using them in a hanging pendant that includes the glass, such as those made by Aquamedic, PFO, or Sunlight Supply. Do check them out! Good luck! Regards, Scott F.>

Lighting Hi guys and girls. <Hello Nick> All of you are awesome and thanks for helping all of us. <You're welcome> I have a reef aquarium with live rock and corals. I need upgrade my lighting so I can get some maxima clams and hard corals. My tank is a 60 gal. Tall narrow corner tank that is like 24 inches tall. I bought a 400 watt pendant metal halide from eBay that someone took down from their warehouse roof. I have read that the pendant MH is not recommended for a good light because of the narrow beam. but because my tank is tall and narrow would it be ok for my application? . I don't want my water to get hot so how far would you recommend putting the light from the water since I have wattage to spare. <First, you won't have wattage to spare. Maximas require at least six watts per gallon.> And would this be too much light for hammer and xenia corals. Thanks for the help and I hope you have a great day! <James (Salty Dog)> - Metal Halide Lighting Acclimation - I have recently set up a metal halide light. its a 17 Watt 10K Reeflux bulb. When I turned the light on for the first time the fish in the tank seemed to become paralyzed looking at the top of the tank. <Well... you just turned on the sun.> My clown fish actually stopped swimming sat on the bottom of the tank just looking up. Is this normal for the fish at first? <Yes... have seen this before. Is much like the oft-repeated interrogation technique in movies - shining a bright lamp in your face; is disorienting.> I know you have gradually introduce the light a little bit every day slowly increasing the time the light is on. <Yes, would be best this way. Cheers, J -- >

Lighting Hi WWM Experts, <Hello, Chris> I apologize for asking the type of question you have probably been asked a million times. I'm on the verge of ordering lighting equipment from overseas (I live in South Africa) and I'm a little scared to order the wrong things (which won't be so great considering our exchange rate to the dollar !), so I was hoping you can give me your insight on this. The dimensions of my new reef tank is 64"x24"x24", holding around 150gallons of water and I would like to keep a mixture of soft and hard corals (we don't exactly have a wish list yet). After doing a lot of reading on your site and in Mr. Fenner's book I understand that I will need in the region of 3-5watts of lighting per gallon for my setup, which gives me 450-750watts. My understanding is that metal halide lights cover an area of about 2 feet with the 175W MH ideal for tanks up to 20" deep and the 250W MH to about 30". So in my mind the options are: a) 3x175W b) 3x250W c) 2x250W I have 2 questions - 1. Am I on the right track here in choosing Metal Halides? 2. Can you recommend one of the above 3 options, or perhaps something completely different? I'm leaning towards 3 x 175W plus a couple of actinics, but it would really be great to have some input from the experts here. <Chris, for hard corals and the possibility of clams, if the interest arises, I would go with the three 250 metal halides, nothing lower. James (Salty Dog)> Thanks again for all your support. Chris

HQI Ballast - 06/03/05 Great thanks. I am looking into drip system for Kalk. <<Great!>> One more thing on Metal Halide. What is a HQI ballast versus a regular ballast? <<Generally speaking, ballasts designated as "HQI" will run about any type of metal halide bulb (single- or double-end...from any manufacturer) within its given wattage. A "regular" ballast will usually only run the single-end bulbs and are sometimes limited to certain bulb/ballast maker combinations. Best to check the specs of the particular ballast in question to be sure. The HQI is more expensive but I am sure it has a good reason. <<If I may...my suggestion would be to buy HQI electronic ballasts. These will run just about any bulb you care to use (within the correct wattage of course), will run cooler than non-electronic ballasts, and will save you a bit of dosh in electricity consumption. They will cost more initially, but are well worth the expense in my opinion. Electronic ballasts manufactured by IceCap Inc. are my absolute fave. Eric R.>>

Metal Halide Shield Hello Crew, I just wanted to thank you for the wonderful service you provide! I have a question regarding my metal halides. I am in the process of constructing a hood for my new lighting (2x250 watt MH and 2x110 VHO). I had always planned on using a glass shield under the lighting fixture. I have been told I would have to use tempered or heat treated glass in the hood. Is this correct? <You would just need tempered glass, a little harder to break.> Someone on reefcentral suggested Lexan for superior UV blockage. Would the plastic melt? <If your halides are eight inches away and properly sized cooling fan(s) are used, this should not cause the Lexan to melt. I would use 1/4 inch thick acrylic.> Can I get away with using regular glass? <Glass does not shield UV as effectively as acrylic.> Do I even need a shield if my lights will be 8 inches off the water surface? <Yes> Any insight you could provide would be much appreciated. <You're welcome. James (Salty Dog)>

Re: Lighting? Sorry about the name Bob. On the way to bed and couldn't really see straight. <Happens> It was a very long day. If it would be alright, I have a few questions for you. My friend happens to be my LFS and says that she can give me the metal halide upgrade for 90 bucks. I am guessing that I should just replace the old system with the metal halide. The system is complete with the ballast, reflector, and bulb. Will this give me full spectrum light (actinic) or do I need to buy more light fixtures. The system is 240 watt. Is it worth it? Also, is it possible to keep Euphylliids? (130 watts) Thank you so much. Brian <All this is posted... on WWM... there are full spectrum and not MHs... Is worth it IMO... good for Euphylliids... Bob Fenner>

Halide Lighting (Mixing Ballasts And Bulbs?) - 05/27/05 Thanks for the info. <Welcome> So I talked to the previous owner and he said they used to have two 400 watt bulbs but by accident bought the 175 and kept it and they used the same ballast as the 400, they didn't change it at all. <Hmm...I have heard/read about ballasts that claim to "adjust" to the wattage of the bulb, usually sold by greenhouse/hydroponics suppliers and geared toward very high wattage bulbs (400w/600w/1000w). I suppose it's possible you have one of these?> Do I still need to change the ballast? <You need to determine for sure which wattage(s) the ballasts are designed for and use a bulb of the correct wattage. If the ballasts are not clearly marked, contact the manufacturer. If you are running a 175w bulb on a 400w ballast it's my opinion you are risking catastrophic failure (explosion) of the bulb.> One more thing, what is the difference between 10k, 14k and 20k? <The "K" refers to the "Kelvin temperature" of the bulb which correlates to color rendition. The higher the Kelvin, the "bluer" the light appears. I recommend 10K bulbs due to their crisp white appearance, which to my eye, provides a more natural appearance than the more blue appearing 14K or 20K bulbs. BTB, even a 6.5K bulb contains more than enough "blue" for the animals we keep, thus choosing a Kelvin temperature generally becomes a matter of what is pleasing to us humans <G>.> Thanks <Welcome, Eric R.>

Reef Lighting...Which Wattage? - 05/26/05 Thanks. I just bought a well established 140 gallon reef tank with 19 fish in it and about 7 different corals and polyps. Everything is running fantastic, the only this is that they have two different metal halide bulbs....One side is a 175 watt 20k and the other is 400 watt 20k....Which one should I replace? Is there a benefit in have one over the other? <My personal opinion is there are very few instances where you really need 400 watts of halide lighting...and I'm an Acropora reefer! I would probably go with 250 watt setups on this system but given your current equipment, my vote would be to replace the 400 watter with another 175 watt setup (you do realize you'll have to replace both ballast and bulb, yes?), and use 10K bulbs in both. Research your corals and place the ones with greater light requirements higher in the tank and I'm betting you'll be fine.> Thanks <Regards, Eric R.>

What's the Diff? Temperature Difference Between Metal Halides Hi, I know that metal halides run hot but is there much of a temperature difference between the 400 watt and the 250 watt halides ? Thanks <Mmm, yes... about 150/250 more... Bob Fenner>

Metal Halide Troubles 5/16/05 Dear WWM crewperson, First let me express my gratitude for your continued dedication to informing uneducated primates like myself on how to better sustain life forms in small, water-filled glass box. <Thanks for the kind words! It really is our pleasure!> I've been trying to get my DIY dual 175 watt Metal Halides working and thought I was successful until this week. The lights have been working fine for the last 3 months, but now that the bulbs have properly "burned in" they continuously cycle (turning on, slowly brightening until they get to a very intense level, flicker then turn off for about 10-15 minutes). I know this is tantamount to a mortal sin with DIY equipment, but I don't remember any brand names. The guy who sold me the ballast 2 years ago said it was 175 watt, so I purchased two 20000 Kelvin 175 watt lamps. I was thrilled when everything lit up and worked, but now I'm wishing I'd just spent the extra money. Is there any way to salvage this situation? Best Regards, James <It sounds like your ballast is mismatched to your lamps. Your ballast components should be labeled with an ANSI number, and if not you can search the internet for a table that will allow you to match the transformer and capacitor ratings to the ANSI number. Lamps are manufactured to work with certain ballasts. See here: http://www.reefkeeping.com/issues/2002-06/jg/ for a great table of which lamps work with which ballasts. This table does not include info for pulse start or probe start lamps (which your 20K's might be). Be very careful working with these ballasts! Charged capacitors can deliver a dangerous shock! Best Regards. AdamC.>

Upgrading to 180 gal from 90 - Lighting options Hi guys, <Hello there> Okay, I have a 90 gal mixed reef and I'm making lava. <Heee!> 2 400w AB 10k's w/2 110w 03 actinics. Before you share your shock, the tank has been in operation for two years and is booming. The SPS are beautiful and I shade the LPS under outcroppings. My yellow Fiji leather is tremendous. No casualties due to lighting so far. <Just strain on your heart when the electrical bill comes> I just purchased a 180 gal acrylic tank that came with 3 150w HQI pendants in the hood w/2 110w actinics. When I make the swap I want to know if you think the 3 150's with 2 - 4 160w actinics would be enough light for the mixed tank or should I use 3 400w MH's (2 of which I currently have on my 90) w/2 160w actinics?

Re: Upgrading to 180 gal from 90 - Lighting options Thanks for getting back to me. <Welcome> Yes, my wife does my CPR with defib every time the electric bill comes in. <Heeee!> For the sake of my retirement fund, I was hoping you would tell me that the lower wattage bulbs would be okay. <Will be> Do you think the SPS corals will have any difficulty adjusting to 5 - 6 watts per gallon from the current 11 they currently enjoy basking (or is that baking) in? <Will do so... I'd cut back the existing over a few weeks time, in anticipation> I have read everything I could find online regarding the lighting options for a 180 gallon tank. Most tanks I have read about are using 3x250w MH in one form or another. I just don't want to under light the tank (spoiled from having the sun in my living room. However, for safety sake, I do use welders goggles to feed the fish, and man, you should see my tan) and sacrifice growth. Does this make sense or am I just being paranoid? <Does make sense, but/and I assure you that the lower wattage is better for your livestock and you... Watch out for melanoma!> I am and will be using AB 10k bulbs (IMHO best bulb on the market) with 03 actinic supplementation when all is said and done. By the way, you guys are the best. I read as much as I can and value your expertise. Rock on! Scott B. <Thank you. Bob Fenner>

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... Thank you very much in advance... Dimitris

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? Thanks, -Will <Welcome, Eric R.>

HQI lighting and UV Hello Bob, Compliments on the great site with all this useful info. What I was wondering: I have a 250 Watt HQI bulb, do I need to use a lens to filter out UV rays? or is this optional? Thanks, Eugene. <AdamC here. Thanks for the kind words! Ordinary glass blocks UV, but quartz glass does not. Although it is not technically correct, HQI has become synonymous with "double ended". All double ended lamps require UV shielding because the outer cover is quartz and does not block UV. All double ended fixtures should include an ordinary glass cover which will safely block the UV. Single ended lamps are build with ordinary glass, so they don't require shielding. Best Regards! AdamC.>

Metal Halide Question Hello, <Hello Brent> I am setting up a 90 Gallon 24" tall by 48" long tank. I have installed two 250 W metal Halide 1400K lights. When the lights are on, shining on the white rock and the white sand it seems pretty darn bright, almost to the point that if you are up close and staring into the tank it kind of seems like it could hurt your eyes. Is that possible? <Only if you looked directly into the light.> If it is too bright, does this lessen over time as photosynthetic organisms begin to cover the rock? <It will.> Also, I need to install some fans but I'm loathe to cut holes in the sides of my nice maple canopy. Is it possible to install them on the rear of the spider reflectors, somehow attached to the rear of the canopy hanging down by a bracket as to vent the heat out the back of the aquarium? If so, how far away from the wall should I have the aquarium from the wall; 6", 8" or more? <Three inches would be enough. I wouldn't exhaust the air in an open back lid. It's much better to have the air blow across the water. And yes, your plan should work. James (Salty Dog)> Thanks, I read your site all of the time Brent

MH Lighting - The Maddox Take Hi, I've read your web page several times. I tried to read your MH FAQ, but man there are 100's and several of them say that "This is the way" and the next one is just the opposite. Don't get me wrong, I've learned that this hobby is just like Religion or Politics, "Every one has an opinion and almost always no 2 are the same. <Hmm...obviously I'M right and everyone else is wrong ;)> Now on with it. I'm putting together a 110g 30" tall glass tank, 48x18x30. Putting in a NNR sandbed which will reduce the depth to 24 1/2". The live stock that I would like to have (hope to someday get, 1 at a time) Open Brain, Green Moon, Moon Stone, Hammerhead Anchor, Green Torch, Galaxy, Purple Elegance, Tongue, and a Whiskers. As for the Leathers I like the toadstools. The Soft Corals are Colt and Finger. I like most of the Xenia's, Polyps, Sea Mats, Mushrooms and the Carpet, Rose and Flower Anemone's. <So much allelopathy in there you'll get cancer! ;) Give the LPS plenty of room between each other, and do run a lot of carbon. Also, I DO NOT recommend mixing anemones with corals - completely unnatural, most always leads to the death of the anemone - I've a very low opinion of those that attempt the mix, frankly. Set up a species tank for anemones, and leave them out of the chemical soup of an LPS\softy tank!> As for fish, I've looked at a pair of Gold striped Maroon Clowns, Regal Tang, Mandarinfish, Royal Gramma, Coral Beauty, and a Flame Angelfish. Plus the norm, Brittlestar, Shrimp and starfish. I will have a 75g sump with PC 96w Quads running at night. I got 2-250w Double end 10K Aqualine by Aqua Medic. They are small hanging pendants, that I want to put in a 16" hood. With 4-54w T5's, 2 Actinic and 2 10K., 2 Moon lights with 4-4" fans and slots in the top of the hood, with an open area in the back in the bottom. The plan is to have the Moon lights and the sump lights on at night. In the morning have the Actinic and the T5 10k on and the Moon/Sump go off. When the MH come on the T5 10K go off. In the evening have the T5's come back on as the MH go off. Then all the T5's go off as the Moon and Sump come on. Now that I read more and went to a Coral store and seen the MH, just like mine running, I really don't need the actinic lights. Please give me some input here as to your thoughts. I was worried about heat, too much light, the MH in a hood etc. I need the hood because the only place that I have for the tank is opposite my TV in the living room. The lights out of the hood, then you can't see the TV. I already have everything ready to go except the Corals and Fish. I have 2-1/4 horse drinking fountains that I will convert to Chillers if needed. Do I have an over kill on the lights? Are the 250w to much, I wanted 175w HQI DE but I don't think that anyone makes them as of yet. Anyway thanks for your time. <For an LPS\Softy tank I do think you have a bit much - you will have to be careful acclimating them to those lighting conditions, plus the excess electricity usage...is it possible to exchange them for 150 DE's? If not, I would either run just the halides (and maybe 1 actinic t5) or even just the T5s without halides. LPS\softies really don't require much light> Rick Johnson <M. Maddox>

MH Lighting - The Maddox Take II So you're saying that I screwed up when I bought the 250's? I was looking for a pair of DE 150's but I could never get the matched pair and the 250's came along so I grabbed it. <Not necessarily screwed up, you still have a nice set of 250s, but for the species you're intending to keep they're just unnecessary> I have the set up for the T5's and an extra ballast for 2 more. I also have a setup for 4-110w VHO. <Well hey if you have those already, go with the T5's and VHOs and use the 250s for tanning ;)> This is my 3rd Reef tank that I am building in the last 10 years. The first went south when I moved. The second died when I went on vacation and my Great Niece threw a bottle of hair die activator in it. <Did you let her live?> So for this tank I was buying one thing at a time so that it would be right when I was ready to set it up. I'll see if I can sell the 250's or trade them for some 150's so if you know of anyone I'm here. <Could try the selling forums on ReefCentral, they get a lot of traffic> As for the Coral/Anemone set up, nothing has been bought as of yet. Yes and you're right in my last reef my anemones spent most of the time hiding in the L/rock except when I would feed them or up high on the side of the tank. The clowns and the Leather, Elegance, Frogspawn, Hammer or Anchor might work together instead of a Carpet. <Yep - and BTW those 250s are waaaay too much for that elegance> When I said that "these are the live stock that I want", that was a wish list. I know that with the size of tank that I have, that there is no way to have all of them. If I did they would all have to be small, but if you do it right, they some day will grow up and crowd each other out. <Just making sure :)> So back to the lighting. What would be the best lighting combo for this setup. 2-150w DE, The T5's and if the T5's were the chosen how many or VHOs and again how many? <6x55w T5s would work perfectly, or 3xt5 and 2x VHO, however you want to arrange it. A good amount of light, but without the massive intensity which isn't needed for the species you're interested in, and in some cases (like the elegance) would be downright harmful> Thank you for your time. <Sure thing> Rick <M. Maddox>

Reef set-up/planning questions 4/14/-5 Hi Anthony, <Cheers> Thanks a lot for the last reply. You gave me the impression I somehow was on the right track. Reassuring. I have a few more questions, I'll try to be as short as possible... -I've read somewhere on the WWM that MH bulbs should be changed each 2-5 years. That surprised me as I thought they needed to be changed each 12 months. Correct answer is once a year, right (and each 18 months for PC)? <Not exactly... it depends on the bulb. Some need changed after just a year of use, while many last longer. Some of the best ones retain over 90% of their efficiency for the full life of the bulb (over 4 years in some cases. I had one go almost 5 years)> -When buying a new MH bulb, there is a warning saying the bulb burns much brighter during the first 100 hours. <Correct> Does one have to let it burn 100 hours before use on the aquarium? <Nope... not needed. But do try to use a sheet or two of fiberglass fly screen (window fabric ) to diffuse light during the break in period> It means I'd have to turn hood upside down and illuminate the ceiling each night during a week, switching old and new bulb each evening/morning... Would be an annoying procedure. -If I go with daily water changes, would 1 or 2% per day be sufficient? <Larger weekly water changes would better help reduce nitrates, etc> -Can I use Selcon in FW as well? <Yes! Lipids/HUFAs are good for all> -How can we know that a certain fish we are buying (from a frequently captive bred species) is really tank bred and not imported? <There are no guarantees... but you must trust your LFS and your own good sense and intuition along with consumer research in advance> I trust my LFS, but I don't know the persons they're buying from... -If I use a Wave2K in my tank, can I place a central LR mound right on it (with clear space in front of vents of course) or do I still have to respect the 3" away minimum...? <I'm really not sure. Do ask of the mfg directly> -In what part of the sump should the evaporation make-up FW (from Osmolator) go ? In the first part with skimmer or in the last one close to the return pump? <The last stage> -Even though they are beneficial, I'm still not sure I want to see worms (bristle, spaghetti...) crawling around in my tank. Can I do as well without them with my DSB methodology (4" in display and in fuge)... <Yes> ...if I rely on Nassarius, micro brittle/serpent stars, amphipods to do the trick (stirring/aerating)? <Yeppers> -I got interested in sponges after going through the Porifera chapter of "Reef Invertebrates". With the mix of corals we already discussed in my last mail (Euphyllia, xenia, and Montipora digitata), could I still add a pretty blue/purple Haliclona sponge? <Yes... and be sure to give it high light and high water flow> And also one cryptic species to make use of the shady zones of my tank (36" hood on a 48" tank = dim light on top sides of tank...)? Here if you could recommend one or some species (I like tubular species or with holes able to provide shelter to other animals) that would fit with my mix (not too noxious) and places where to find them. They don't seem to be readily available... <Have you read the writings of Steve Tyree on the subject of cryptic refugia? Google until it hurts :)> -Should I forget about keeping a crocea clam and a Lysmata amboinensis in the same tank? <It is risky in the long term> And what about a single specimen of "micro-hermit"? Very likely to pick on the clam I guess... -About phytoplankton reactors. I have seen heavy set-ups with reactors on the net. I think I don't want to get too involved with these. Would it still be worth it to simply use a single 2l pop bottle dripping in the fuge (as seen in Reef Invertebrates, p.54) without adding culture media. Would only use a strain to start the culture with new seawater (made from RO-DI) and no additives and adding new seawater as need is to compensate for the drip. Would it still be useful? <Yes... it certainly can be :)> BTW is there not phytoplankton in the system anyway, especially when using a lighted fuge with macro-algae? <Yes... but there just is not enough produced naturally>> -Back to the subject of getting an ocellaris to host a coral in my tank. I tough I took a step in the right direction by forgetting about the BTA and use a coral substitute. <Excellent! thank you> Seems I'm dead wrong again with Euphyllia. With the set-up I'm planning, I wonder if it's even worth trying to have an ocellaris at all. Let's say I have 2 or 3 Euphyllia and an awful lot of xenia (hopefully:). I guess it's maybe possible that the ocellaris would favor xenia and only host the Euphyllia from time to time. <It is possible> Is it something possible to have the corals in a set-up "share the burden" of a clownfish thus being able to get along with it? <Rather than stress the corals... my advice is to forget about the mix in a garden reef tank, and set up a dedicated anemone tank, my friend> Ok, Thanks again!!! Dominique <Kindly, Anthony>

Lighting/Metal Halides Hey Guys, <Hello Ryan> I am truly addicted to your site. I read this site and all of the FAQ's almost nightly. I feel like I owe it to my aquarium friends to provide the best light possible. I have one question in regards to an upgrade in lighting. I have been looking over MH and PC for quite sometime and have decided to go with the MH for multiple reasons; longevity, appearance, intensity and price I found to keep my first Anemone. I have an 80 Gallon standard tank 48X18X24" deep. If I get 2-250 Watt MH retros to install in my canopy will this be sufficient for mostly SPS and an Anemone? <Yes> Also where do you place these Retros for maximum light distribution? I thought perhaps just centered in the width and placed at 12" and 36" across in the length of my canopy. I hope my question makes sense and I would feel honored to have you write me back. I use your advice as fact. Thanks for everything, Ryan Willard in NORCAL. <Ryan, I would put them at 16" centers and would use bulbs in the 10-14K range. James (Salty Dog)>

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

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 Halide question 3/30/05 Hello, I have read through all of your metal halide FAQ's with regards to a 90 gallon reef aquarium. My aquarium is 48"X18" by 24" deep. The tank has been running for a month now without lights and I'm now ready to install them. I definitely going with metal halides. I want to keep mostly SPS and Clams. What wattage should I be choosing? 175, 250 or 400W? Marine Depot is recommending 400W. <400w would be overkill IMO. If you use quality reflectors and keep the clean and keep the water clear, I don't see any reason to go over 250w, even for SPS and Clams. In my experience with 400w MH, many corals had to be place very low or in the corners to prevent OVER illumination.> Also, should I be supplementing this with power compact lighting? I read about a lot of folks supplementing their MHs with power compact and wonder if I should be as well? <This is purely an aesthetic question. I prefer VHO over PC, but actinic lamps in either format can be used to add more "blue".> Also, can you recommend a type of ballast, for example Ice Cap? <Icecap ballasts are great, and their customer service is very good. The premium price of electronic ballasts is quickly paid for in increased lamp life. If you want to save on up front costs, most companies use internal components from the same couple of companies, so shop customer service and price.> Additionally, do you prefer double ended over the standard bulbs? I will be installing these in a custom canopy that is 16" high. Should I be looking at retrofits or explore pendants? Many thanks in advance. -Brent <The reflectors for double ended lamps generally reflect more of the light into the tank than those for single ended lamps. Do search the archives at www.advancedaquarist.com for Dr. Sanjay Joshi's studies on lamps and reflectors. The choice between retrofit kits and pendants is mostly a function of how handy you are and how frugal you are. Best Regards. AdamC.>

Metal Halide Question 3.25.05 G'day <Indeed! Ryan with you today.> I've just located your site which I might add I find fantastic. However I still have a lighting question. <Shoot> We are new to Marine Tanks after keeping tropicals for many years. We have a tank that is 500 litres (sorry for the Imperial measurements but I'm in Australia) the measurements are 30" Deep 30" Wide and 4' Long. Can you advise on the best lighting? <Only metal halides create enough usable light in the depths of a 30 incher! I would recommend a pair of pendants.> We currently have 1 double compact with 1 white bulb and 1 blue bulb, 1 moonlight and dual 4ft fluoro being one blue bulb and 1 white bulb. All are around 37 watt (this does not seem high enough after reading your site?). We also seem to end up with a lot of yellow light in our tank that make the tank look dirty or "acidy". <And the water itself at this depth filters most of the usable light.> Our tank seems healthy and we successfully keep Leathers, Bubble Coral, Morphs, Cushion, Torch Coral or Finger's, Jardini's and soft tree's, we are unable to succeed with hard corals they all die Dunno why. <Yes, you do! You have identified it in this email. Combine a new lighting system with proper calcium/alkalinity levels, and they will take off.> We are looking at MH Lights but find they are too expensive to purchase and run but we are unable to work out the best lighting for looks and for growth. Everywhere we go that have MH's their tanks look amazing and I say that's what I want but after reading a lot on your site I believe I can accomplish both looks and growth with less expense. <You can build your own metal halide for CHEAP. Are you handy? ozreef.org. If not, look for used lights- They are typically only in need of a bulb change, and you are back in action. Good luck, Ryan>

Metal Halide Lighting Hello crew how are you tonight? Well anyways I would like to ask you a question about metal halide lighting. I have a 60 gallon FOWLR that I would like to make a reef. Would 2 - 400 metal halide bulbs be over doing it? I think it may be a little overkill. On my calculator I punched in 400 x 2 equals 800, divided that by 60 and came out with a whopping 13.333!! That would mean I'd have 13 watts per gallon?!! Is that to much for corals? Also Ritteri and BTAs? Well I'm in a big hurry so if you would try to reply back soon. <Chase, two 175MH"s would be plenty for keeping anything. That gives you 5.8 watts per gallon. I would suggest 10K bulbs. James (Salty Dog)> Thank your great crew! Sincerely, Chase Simmons

Lighting for S/W Hi James. <Hello Mark> I can only afford one 150w M/h (Arcadia Series 3) for my 32x18x18 tank. Which will put it directly over the brace (Great) Never simple, is it?. Do you think I need more light? I have a few soft corals. Planning on an Anemone and some hard corals in my new system (Miracle mud refugium too!) Local shop told me that I could put two 3" braces either side of the 6" brace in the middle, then take the larger one out. Can the braces be put at either end of the tank to form a square with the other braces running along the back and front panels. Why does the tank need these braces at all? 8mm glass doesn't flex, does it? (Sorry, rhetorical questions ...) This brace is driving me bonkers. Great site, thoroughly enjoyed. That's all for now. <Mark, to protect the warranty of your tank, I would contact the tank manufacturer about the change in bracing you want to do. My thinking is the manufacturer isn't going to spend any money on materials if they aren't required. That would be enough light for one side of the tank, or the middle area, but not enough to place corals anywhere in the tank, they will have to be under the light wherever it ends up. James (Salty Dog)>

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)>

Lighting/MH First of all. I just found your site and think it is fantastic. I am relatively new to reef keeping and have a question about lighting. I currently have about 4 watts per gallon (PCs with actinic supp.) but was told by my LFS that in order to keep some of the clams and stonies I wanted I would need 8 to 9 watts per gallon. Without researching (I know. I'm an idiot) his claim, I went out and bought 2 x 400W 14000K Metal Halides (and all the fans, ballasts, etc) which will bring my tank to 8.6 watts per gallon. Now, having read a lot on your site, I am worried that I am about to bake up some livestock. For a 93-gallon tank, is 800 watts way too much? Or can I slowly acclimate the tank and get away with it? Thanks, Michael Stoner <Mike, it's not an unusual amount of light for keeping SPS, LPS, and clams. As you say, slowly acclimate the critters to the higher intensity lighting. I think you will love the way it will look. I envy you. James (Salty Dog)>

Lighting for S/W Hi there. Have just gotten new tank 32X18X18 (Inches) small I know, but it's custom cut for an alcove. Thing is it has a brace, 6" wide, across the middle, from front to back. Will this affect the lighting in this area of the tank. Am thinking of getting 150 watt MH. That's all for now. <Yes, it will affect the light, Mark. If you're planning on SPS etc corals, I would go with two 150's and place them in the open areas. If no hard corals, two HQI 100's would be OK. James (Salty Dog)>

Metal Halide/SPS Corals After doing a search of your site I do have a question about halides for SPS corals. I have a dual 175 watt metal halide hood that is over a 46 gallon bowfront tank. Presently it has two Sunburst 12K lamps. I have heard quite a bit of mixed opinions on these lamps and would appreciate your opinion. I realize that these lamps have a lower PAR due to their color temperature, but are they satisfactory for the color maintenance of various SPS? I would also like your opinion on using higher Kelvin lamps for color maintenance, i.e. will 10K lamps supplemented with VHO actinics provide the proper mix or are 20K preferred? <A lot of people are just using the 20K's now. Haven't heard anything negative. I personally prefer very little actinic in a lighting system. Here is a link I'll post. Adam Blundell wrote this article concerning coral fluorescence for Advanced Aquarists On-Line Magazine. Think you will enjoy it.> http://www.advancedaquarist.com/issues/feb2005/toc.htm.> Thanks you for the help and I look forward to your response. <You're welcome. James (Salty Dog)> VHO/Power Compacts VS Metal Halide By spending an outrageous amount of money in this hobby I have learned a few things that have led me to believe that the simplest way to setup and maintain a Reef tank is to stick with the basics and not to go overboard on the vast amount of equipment available (I should write a book on what not to do in the Reef hobby). <Please do> Now with that being said, I was thinking about changing my current lighting from VHO/Power Compacts, 2-VHO/White/Actinic 1-VHO Actinic & two 96W 50/50 Total of 672W to a new Aqualight Pro, which has 3-MH, 4-PC & 3-Led lights giving me 834W. I have a 135g Oceanic with Sump, Remora Pro, two Mag 9.5 Returns and 3 Tunze 6060's... <Heeeee! A larger heater and you could make this into a Spa-bath!> ...with about 300 Lbs. of Live Rock and a 3-4 inch sand bed. I would like to know before spending this kind of money if I would be gaining that much? <That much.... for...?> I understand that I am increasing the amount of wattage, but am I also gaining a "new look" within the tank that I will be pleased with? I would appreciate any advice you can give me. Art McKinney <Mmm, not possible to render subjective evaluations for others... that is, what you might be pleased with is not within my domain of assessment... Depending on what you hope to "accomplish" functionally (boost growth? Color?) or aesthetically (again, up to you), you might be better off investing your funds in... a calcium reactor... an ozonizer... perhaps with a desiccator... A new refugium... another tank! Bob Fenner>

Re: VHO/Power Compacts VS Metal Halide and The Toilet Bowl Syndrome Thank you for your quick reply, the Aqualight Pro runs about a $1000 for the lights and accessories. <Yeeikes! New idea... save this money up and come on out and stay with a bunch of the WWM Crew at out house... for a month, diving, hiking enjoying yourself in Hawaii... April... take a look for airfares... think of the enjoyment of just the anticipation...> I guess what I was trying to ask is if the light output from the Aqualight Pro would be better than the VHO lights. I am not sure what the Spectrum is for VHO's compared to Metal Halides so I am not sure if I would be gaining anymore than the wattage....Spa, funny, everyone says we should have flow within the aquarium, the sad thing is that all of my fish are plastered to the glass. <I'll bet... AM serious re HI. Bob Fenner>

Of VHO/Power Compacts vs. Metal Halide and Tax Returns Again, thank you for your quick reply and the invite to Hawaii....When I see my Tax return I may have to take you up on this offer:) So, are you saying that I won't notice a difference going from the VHO setup to the Metal Halides?

Upgrading to halides in the UK Dear Crew <Hello Jim, Justin here.> After much deliberation and soul searching I am considering upgrading my lighting to a metal halide set-up. After reading the conscientious marine aquarist I have a few pertinent queries for an old UK reefer like myself. <Sure will do my best> My current lighting is as follows: 4 58W Arcadia Marine whites 1 Actinic 03 1 T5 80w Totaling around 300 watts of light. <good setup but what sized tank?> I currently keep a few hardy stony corals with some soft corals in a well pruned reef garden setup which consists of 2 Euphylliids 2 Caulastreas 1 Porites (growing very slowly under the strip lights) 1 Pavona 1 Montipora 2 Turbinarias Various Sarcophytons, cabbage corals, and polyps. These are placed as per the coral requirements around half way to within the top of the reef wall in my 120 gallon set-up. <Good to see and not a lot of light for a 120 at depth so good to see them being near the top.> This 300 watts has served me well and as you probably all know halides are expensive but remove the need for all my fluorescent ballasts etc. <Yes and no... You might keep the actinics to get the color you want, or go with 10,000k MH lights to get those blues as well, but that is based on your personal tastes.> I would like increased growth from the halides but I am worried about 'scorching' the corals with an upgrade to the Arcadia 400watt pendants (6 foot triple halide unit) <A concern yes, do acclimate them using short photoperiods, some grating to break the intensity down and lowering the corals some, as well as lowering the light unit very slowly to no lower than 7 inches. those 400's may need 10" height to keep things cooler. > I am eyeing up. I can acclimatize the existing corals by shifting the unit away from the aquarium and bringing it in slowly. Also I am considering a fan for cooling, alas a chiller is well out of my cash reserves resource. <Please do this as well as buying some egg crate to diffuse the lighting, read on the FAQ's for more info on that. Also you will need a lot more than 1 fan to cool things down. If you cannot afford a chiller maybe look into 250 watt halides that run cooler and use fans to cool the lights and blow across the surface water to cool it more.> Mr. Fenner seems Initially skeptical of halides in his book but I fear the stony coral growth is just too slow with strip lights for my liking. <Not sure on that as I have not read his book, however halides are not lights that people should normally use as they can be dangerous, can overheat the tank, and can scorch and bleach corals.> Wondered what our thoughts and recommendations are. Thanks Jim <Good luck on this as proper lighting is a tough question to decide. I would go with 250watt lights as a max, unless you can get a DIY chiller out of an old fridge or something as MH lighting can drastically raise water temps, very easily. Good luck and hope your stonies do better with these lights.> <Justin (Jager)>

MH Lighting Date: Wed, 09 Feb 2005 I am really amazed by how much info you have on your website. I am in the process of upgrading my 55 gal reef to 155 gal. I am planning on having soft ,SPS and some clams. I had my soft corals now under pc lighting. My question is, what kind of metal halides and do I still need actinic lighting with that or not. I saw a guy who keeps his 155 gal reef under 3 HQI bulbs,250 watts each,13,000 k .What do you think of those??? He does not have actinics and his corals and really fascinating. Thanks. <Hello Ramy, My suggestion is, for the corals and clams your interested in would be three 250 watt metal halides and two 96 watt PC actinics. This is assuming your tank is 60"x24"x24". As far as the HQI bulbs, I don't think they are any better than the standard metal halides, they cost a bit more. But, being you want to keep SPS and clams, you will need at system like this, especially if you get any T. crocea clams which do require very strong lighting, and are the least hardiest of the clams with T. derasa being the hardiest. Good luck. James (Salty Dog)>

VHO--->HQI I have read much of the info in the metal halide FAQ's and would like your advice. <Will gladly render my opinion> I have a std. 55 gal tank that is currently lit with 4 110W VHO's. I would like to add a clam, and I think I need MH lighting. <Depends... on the species... its placement... your desires for rates of growth... other co-factors like water clarity, alkalinity, alkaline earth concentrations...> I am thinking of installing a 150W double-ended 10000K HQI light on one side of the tank. I was thinking of retaining the 2 outside (front and rear) VHO's but I think the HQI fixture is too wide to permit that. is the 150HQI of sufficient wattage (and 10000K right temperature) for that end of the tank--or should I use a 175 or 250 MH? <If it is for just the clam/s, I'd go with the lower wattage... if you think you might get very involved with SPS the higher... or two 175s... and a calcium reactor...> I would then re-use my existing VHO ballast by installing 24" VHO's in the other end of the tank. While the canopy is totally enclosed, I have 2 ventilation fans installed, and room for 2 more if necessary. <Good> Thanks! Ken Baker <Ken, do look into the added upkeep you will be inducing here... as well as the incipient operation costs... for electricity, lamps. Bob Fenner>

Re: VHO--->HQI Bob--thanks for your quick reply. You've given me the info I needed, and will do a bit more research and introspection on planning for future livestock before a final decision on wattage. Having said that, there seems to be lots of "opinion" here in the FAQ's that 250W is a bit too much for 15" depth (std 55gal minus 3" of substrate). <Mmm, do check this... most stock 55 shows are 22" in depth> Given the inside height of my canopy, I will have the bare minimum 6" between the bulb and the water surface. <This IS of concern... for waste heat, light spread... as well as dangers of splash and spray on the lamp/s> Here in central Indiana we are fortunate to have reasonable electricity rates, so adding an MH won't kill me! <We'll see... a dear friend owns a shop here in S. Cal... told me folks just brought in and dumped their MH's when rates here trebled (more thievery by the Gov't really)... and simply walked out... Bob Fenner> Thanks again, Ken

LIGHT CONTROL Sat, 5 Feb 2005 Hi there. I am currently having problems finding a timer to control lighting needs. Specifically metal halides and moonlight. Do you know of any products that can control when the MH come on and go off as well as control intensity of moonlight? I know there has got to be some out there. I tried CA, Champion, MarineDepot, etc. to no avail. Thanks for your help. <Tazzis, I have just the product for you. It's called the Active Home Pro USB 2-way Home Automation System. The beauty of it is that you control the system with your PC. It sends digital signals through your home wiring to turn on/off modules that you employ. Dimming modules are available for MH/Power compacts providing your ballast is electronic and has dimming capabilities. Best of all the basic system is $49.00 plus the modules you select to use. Modules are anywhere from $14.00 to $20.00 depending on what you want. You can turn the system on/off as many times a day as you like. Use it also to shut powerheads off/on. The site to go to is www.x10.com. James (Salty Dog)> Lights and protein skimmer Thu, 03 Feb 2005 Hey WWM crew-A few quick ones. First, I just purchased a double 175 MH hood setup for my 65. I hung it above the tank because I have no hood. (tank is built into the wall with a dedicated room for equipment behind it). There is a Plexiglas strip protecting the bulbs. Should I still keep it 8" above the tank, and should I remove the Plexiglas strip for more light intensity.<Keep the acrylic strip, it serves as a UV filter, and you could lower the lights some as long as the tank is still lit completely.> Second, I plan on adding a 38 gallon refugium. Can I put my protein skimmer (Remora Hang-on) in the refugium, and if so, should it go before or after the deep sandbed section. Thank You Brian Cooper

MH question Hi, I have a 5ft L X 2ft W X 75cm H and was just wondering would 1 X 250watt metal halide placed in the middle be enough for soft coral and host anemones to live???? If not then what else would you recommend with out breaking my wallet???? <Dana, that wouldn't be enough unless you put your corals etc in the center of the tank. The ends of the tank wouldn't be all that bright. If money is the object you might be better off with a PC hood with four 65 watt tubes. These are $212.00 plus shipping from Drs. Foster & Smith and they have a built in cooling fan along with two lunar lights for a nice night effect. They are listed under the brand name "Satellite" although the units are made by "Current". James (Salty Dog)>

MH question more Follow-up Date: Wed, 2 Feb 2005 Hi, My Tank has 3 braces on it so how would you do it?? <You can use a retrofit kit and mount them in a hood or you have the option for a hanging pendant.> Also how much are metal halides to run power-wise? <Dana, that all depends on the wattage of the lamps and the type of ballast you are using. The electronic ballasts will use a little less current and extend the bulb life along with slightly increasing the intensity of the lamp. James (Salty Dog)>

MH question follow up 1/31/04 Hi, I live in Australia do you know somewhere I can get them from here, Also is 3 x 150 watts MH alright for my size tank? Thanks <I would suggest searching the 'net for an aquarium club in Australia. They will be able to give you better info on equipment availability than we would. I would suggest 2-3 lamps to cover your tank, and in my opinion, 150w is plenty for 90+% of the corals you will probably keep. Best Regards. AdamC.>

- IceCap Wiring Information - Hello, I was just wondering if you had a direct route to info about IceCap Industries Model 660 Electronic Ballast. Like, where the wires go and what colors... Thanks for the help! <For all information IceCap, please go here: http://www.icecapinc.com Cheers, J -- >

MH over heating Hi, Just wondering how to cool Metal halide lamps down would you need a fan built in or an external fan???? what is the best option??? Thanks <Please read here: http://www.wetwebmedia.com/marcanopies.htm and where the linked files (above, in blue) lead you. Bob Fenner>

Need a glass shield for halides? Hi, and thanks for reading this....My question is regarding a 250 watt AB 10 K Mogul Bulb or any screw type metal halide bulbs...Do they need to be shielded because of UV rays or is the bulb case already producing the shielding effect ? < They do not need to be shielded. With the double ended bulbs it is a good idea, but for mogul base you are okay. > The reason I am asking is I wanted to maximize the amount of penetrable light into the tank...120 gal Standard Tank 19 inch water column after sand bed....Bulbs 9" from water surface... < Yes, you do cut down on light when you add the shield. Therefore I try not to have a thick shield. I like using 1/8" glass. It isn't very thick but it shields. Plus, I would rather clean the salt creep from my glass, than from the bulbs themselves. So a glass shield also helps with maintenance. > < Blundell >

Juwel Trigon 190 Litre - upgrade to MH 1/16/05 First post - thanks for your site - great! <cheers... and welcome my friend> I have a Juwel Trigon 190 Liter bow fronted tank with 1 x 18W 24" Arcadia Marine White and one 18W 24" Arcadia Actinic. I am keeping a few polyps and want to house a greater selection of corals. The polyps seem to have lost their 'greenness' and are looking brown - although apart from that they are looking healthy and opening out. <the lack of UV and overall light intensity is the root cause here> I want to increase the lighting intensity and have been looking into an Arcadia 3 Series 70cm 250W HM bulb with 2 x 18W actinic bulbs. <very fine choice> This unit hangs from the ceiling - which is necessary as other style units would not fit onto the bow front. Is this a suitable selection for a tank of this size (43 UK Gallons) <yes... quite fine. Its a touch on the bright side, but no worries... especially with the common tendency to use bluer lights> Given the existing lighting scenario - is there a significant difference between the light output of what I have and what I'm looking at - <yes... tremendous. Acclimate the present corals slowly to the new light by use of the "screen method" (do a google search of our website wetwebmedia.com from the index page to find more info on this)> and what height above the water should I have the MH kit before lowering it down for acclimatization. <about 25 cm. off the water surface or higher for its final resting place. No need to start it higher at first if using the screen method> Thanks for a great site. Tim - UK <best regards, Anthony>

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? 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>

MH Lighting Question <Hello Brandon>I've got a question on MH lighting. I've currently got a 3x250W system running with 2x96W actinic PCs. The MH bulbs are 10K XMs. I'm thinking about switching the system to 3x400W so that I can switch to the 20K bulbs. The PAR values seem to be horrible on the 250W bulbs. Is it worth the extra expense to go to 400W bulbs? I'm not sure how much the PAR would increase going from 250W to 400W on a 20K bulb. It just seems like the most popular reefers, like Tyree for example, are using 20K bulbs to get extreme colors on their acros. Any thoughts on the 20K colors, and the extra heat it would bring? It's a 125G tank, and I'm wondering if 3x400W would be overkill or cause much more heat? <Going to three 400's would definitely increase the heat level. If these are pendants you could probably get away with it. If they are hood mounted you'd probably have to go with a chiller. I don't think the extra money for everything is going to be cost efficient. Drs Foster & Smith sell the German MH bulbs in your wattage and in the 20K you desire. James (Salty Dog)>

MH Lighting Hi, I'm planning a lighting system for a 215 gal reef rank. I want to keep some SPS corals, clams, and some softies--a full blown reef tank. I have a PC fixture that will produce about 200 W of actinic light. I'm thinking that I will need about 800 more watts of light.<your figures are correct.> At this point, I think that two 400 W MH lights would be the best way to fill that gap. Please say if any of that sounds like a bad idea. Since it's a pretty large scale lighting system, I'm obviously looking for ways to cut costs. I'm somewhat handy, so my plan is to buy some pretty good ballasts and bulbs and to build the fixture myself. I wondered if you could recommend one or two ballasts. Can you comment on the 400W Universal Magnetic M135 Ballast -Pulse Start Metal Halide they sell on hellolights.com for $86.00? Any information you could give me about MH ballasts would be greatly appreciated. Should I use 10,000 or 20,000K halides for my application?<10K or 20K, the choice is yours. The Universal ballast will work fine, especially if your on a budget. The electronic ballasts do increase bulb life and intensity. Another ballast would be the "Blue Wave brand". They usually sell for about $100-115 on the internet. James (Salty Dog)>I really appreciate your site and the Conscientious Marine Aquarist, a great resource that I consult often. Thanks very much, Justin Armstrong

Kelvin Temp - 1/13/05 I have read your lighting FAQs and haven't seen my particular question. <Then you missed it! It's on lighting FAQ page 3, answer #14, paragraph 2, line 26, letter 47. Just kidding> I have a 225g reef that is 30" deep. I have two 400w HQI Pendants with e-ballasts about 9" above the water. Tank is at 80-81 stable (Night/day). My question has to do with the temperature of the bulbs. I don't have any other lighting and was wondering if I don't have adequate red green spectrum? There is plenty of intensity.... to the point where mushrooms, softies, etc need to be place in the centre of the tank on or near the bottom (two coral head reef setup) for them to open fully. So my question is: Provided you have intense 20k lighting... is it still necessary to have lighting in the 6500, 10k 14k area? <As I am not aware of the species you are attempting to keep, I will provide as general answer as I can...at least for the species commonly kept in this hobby. Most photosynthetic organisms from tropical reefs prefer 'warmer' Kelvin temperatures (5500k-6500k range) as they evolved to utilize sunlight, which is 5500k. However, they are for the most part very adaptable, and should do fine with 20k lighting. They will not grow as fast as they would under a warmer bulb, though> Thank you for your help..... and what a great source of info your site is. It is my primary source when looking at new specimens or problems. Thank you. <You're very welcome - we try!> Scott McAdam <M. Maddox>

Upgrade to Metal Halides? Good morning, <Hello Ralph> My reef aquarium has been up and running for a year and a half. Right now I have 260 watts of PC lighting and am interested in upgrading to Metal Halides. My question revolves around my beautiful cover of coralline algae. Will the sharp increase of light intensity burn or destroy the nice color or will it adjust to the new light intensity.<It will adjust, though I would recommend starting the halides at one hour and increase by one hour daily> The aquarium is a standard 75 gallon. Currently we house a variety of soft corals and mushrooms. We have a small Montipora frag we are trying to cultivate. Everything is happy and looks great but we are interested in taking things to a new level with some SPS coral. Will and additional 260 watt PC fixture have a similar effect to adding the metal halides.<Another 260W fixture would give you 6.9 watts per gallon which would be plenty. I believe your 75 is 18" deep. Halides generally penetrate the water deeper so you might want to try adding two 175W halides to your existing fixture. Personally I like the effect 10K lighting does to the appearance. James (Salty Dog) Thanks, Ralph

Re: Upgrade to Metal Halides? Dear James, Thanks for your quick reply. Assuming I go with the metal halides, will I need to do anything special to protect the mushrooms. Currently they are deep in the aquarium (near the bottom) and off in the corners. I have read that mushrooms do not necessarily like the intense lighting halides provide.<No, just acclimate to the halides. James (Salty Dog) Thanks, Ralph

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 >

Metal halides over the center tank brace All: < Blundell here tonight. > Thank you for your valuable advice. I am in the process of upgrading the lighting on my 125 gal. 72X18X22. I will be going with MH mogul based in 20K. I will be purchasing a new canopy in either 10" or 12" depending on your advise. I wish to keep LPS, soft and limited SPS. I will keep the SPS confined to the upper 1/3. I know these are broad categories, but I will place specimens as needed. My question is should I go with 3 X 175 watts in a 10" canopy or 3 X 250 watts in a 12" canopy? < With those options, I'd chose the later. The more watts the better in this case. > I have never kept SPS but it is my understanding that 20K bulbs don't put out the same PAR per watt as say 6500 or 10K's. < Very true. 20k have better color for the corals, but grow slower and don't look very bright. I use 20k now, but will probably switch to 14k or 10k next time. > Also, there is a 12" 1/2" thick center brace that one of the three lights will be directly over. Is 10" or 12" of clearance in the respective wattages safe? < It is safe, but the shadow of the brace really cuts down on how well that bulb will work. You may want to have that brace replaced with acrylic, or have your lights staggered so that the middle bulb isn't right over the brace. > The canopy will be well ventilated (fans. etc.) Thank You! Ben < Blundell >

Mixing MH Wattages Hi, I have 3x175W (6500K) + 2x140W VHO (1 super actinic R, 1 actinic white). I'm considering upgrading the middle MH bulb/ballast to 400W. Is that a bad idea to mix different wattage metal halide bulbs? I have a 6' 150 with 'usable' dimensions of about 72L x 24H x 18W. Also I currently have glass covers on top of 2/3 sections of the tank (just sitting on the braces). I did that to reduce splash onto the halides in the canopy but now those glass tops are getting covered in salt. Is there a material that will not accumulate salt and will let most light pass through them? Thanks!! <Hello, I don't see a problem mixing the two different wattages except that the corals might be shocked. I would put the higher light corals in the middle section where the 400W metal halides are going to be. The best thing you can do about your lids is to clean them weekly. Good Luck. MikeB.> Metal Halide retro question Hello, First I would like to thank you for you wonderful web site, great job! My question is I have found the following 175W metal halide retro kit and wanted your opinion overall if I should consider or pass. Everything is brand new from petmeister.com. The included bulbs are Catalina 175 Watt 10000K mogul based and the ballast is a Fulham Workhorse. They claim the ballast is compatible with any 175W mogul base bulb. I am not familiar with these brands. They are asking $229 for the retro kit which includes 2-175W bulbs, magnetic ballast for 2X bulbs, socket, reflector, mounting hardware & wires. I would replace the reflectors with spider reflectors for better light reflection as I am sure the basic ones included are not sufficient. Is this retro kit worth anything or should I spend more $ and go with more common brands such as Icecap, PFO etc for quality reasons? Any input would be helpful. Thank you for your time. Miles <If it were me, my system, I'd return this gear and go with well-known brands. The Fulham brand is the real thing, but the lamps are engineered for outdoor landscape use... Bob Fenner>

Lighting change I have a 50 gal. that is 18" deep. I have 1-250 watt mogul base MH about 6" above the water. I am replacing that with 2- 250watt HQI, 2-T5 actinics, and L.E.D. moonlight. The tank has been with the single bulb set-up for about 1 year. My question is how should I go about acclimating the stock to the new light system without shocking them? Thomas Giddens <Hello Tom, A safe way is to start the MH's at one hour, and increase by one half hour each day till you reach the time you want your lights on. James (Salty Dog)>

Lighting for a 360 gal I just bought a 360 gallon acrylic aquarium and I am working on the placement for the MH. I have four 250 Watt HQI MHs. << Sounds good, I'd consider 400 watt halides but you should be fine. >> The tank is 6' wide, 4' deep, and 2' tall. << Only 2 feet tall? Then 250 watts should be good bulbs. >> I have read that you should place a MH lamp every 2 feet. So I would have two rows of three lamps for a total of six lamps. However, the middle of the aquarium top is all acrylic. I have read on your website that you should not place MH lights directly over the acrylic and try to place them in between the opens. If I am to do this I would be able to fit 6 lights over the aquarium. My question is this. Should I just have 4 lamps over the openings or should I have 6 lamps and have 2 of them over the acrylic top? << Ooh tough question. I'd probably go with four bulbs at 400 watts each, or four bulbs at 250 watts but add some VHO actinics to go with them. On a tank that size, I'd even consider 6 bulbs over the open areas if you can fit them. >> As always... Thanks for your help! << Good luck, nice sized tank. >> Steve << Blundell >> 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>

Metal Halide Lighting 12/22/04 Hi, I have a 5ft L x 75cm H x 58cm W and was wondering how many metal halides to buy????? (I was told that 3x 150watts would be good). <The general rule is to cover about 2 ft per MH lamp, so your tank falls in the middle of two or three. If you have center brace(s) over your tank, I would let that decide. Never place a MH lamp directly over a center brace (acrylic or glass tanks).> I was wanting to keep soft corals and anemones and what is the best Kelvin for these species. <Two or three 150w or 175w lamps would be fine, but the anemones would have to be closer to the light.> Also with metal halide can you use cover glass??? (I was told that it blocks out most of the light) (but the fish might jump out) ??????? Thanks <Although fish jumping can be a problem, I would only consider tank cover glass if you are keeping notorious jumpers (jawfish, firefish, etc.). Even then, the downsides (reduced evaporation, higher heat retention, light reduction) are great. Best Regards. AdamC.>

Lighting Follow-Up Ok, just suppose that I'm going to switch to MH, what would be your recommendation according to my tank length 4 feet and depth 1'3" in number of lamps, watts for lamp and ?k ? <?k truly depends on the type of coral that you'd like to keep- Deeper blues are typically used for deeper water corals, and more whites are for shallow and lagoon corals. I'd recommend a combination of the both if you'd like to have keep all types of corals. 2 lamps should cover the tank nicely, and between 5-9 watts per gallon is a nice wattage. Good luck! Ryan>

MH upgrade questions Firstly let me thank you all for this invaluable and top notch resource! Always the first place I turn to for reef setup info. <Thanks, same here :)> Three months ago, I upgraded from a 30g oceanic "cube" to a 75g RR AGA with 20g sump and 10g gravity fed refugium. <Neat, I love refugiums> Transferred livestock, now in new tank, consists of 2 Ocellaris, 1 RBTA, a few zoanthid colonies (I do not plan on keeping any LPS, SPS, or different anemones, by the way, in keeping with the needs of the RBTA.). I have a 4-5" DSB <excellent> (so the water column effectively is only about 14-15" deep), and 75lbs of live rock/rubble. The lighting system which was on the 30g, an Aqua Medic Aquaspacelight-mini 150w (with electronic ballast, and AB 10,000K DE bulb) is now illuminating one half of the new tank, where I have placed the zoanthids, and where the anemone has apparently agreed to stay put. <Unlike mine at the moment...> I plan on getting a second MH pendant, and was considering an equivalent setup for the other half of the tank until I saw a friend's aquarium lit with AB 20K DE bulbs--and absolutely loved it. <About to get a 20k bulb for my halide...PC fixtures are annoying> I am concerned however that the lower light output of the 20K bulbs would slow down zoanthid growth. Would it be advisable, with 20K bulbs, to get a 250w pendant for one side of the tank, even if that meant slightly uneven illumination, to make up for the lower light. <Just how fast do you want those zoanthids to grow? As always, the farther away from 5500-6500k the slower growth you'll see, but I doubt it would be more than barely noticeable in a hobbyist setup. Zoanthid growth is more inclined to change between species more than anything: I wouldn't worry about it> I would have the whole tank be lit by AB 20K bulbs, starting out small colonies under the 250w for accelerated growth. Is it safe/recommendable with 15" water depth. <Not needed with your water depth\stock, but entirely doable...consider some maximas\Croceas while you're at it ;) Mount the lights ~10-12" above the surface, to avoid shock\overheating> How would the RBTA likely handle the shift in color temp and intensity? <Shift shouldn't be much of a problem, but make use of the screen method to acclimate to the intensity> The other concern for me is electrical cost-- I live in California. I plan on getting an electronic ballast, either way, so as to cut down on the heat which tends to be a problem in my small fish room. I am currently looking at the Geissmann Nova pendant, with its remote ballast (the electronic ballast on the Aqua Medic has been giving me problems--I'm hoping that having a remote ballast away from the heat of the bulb will ultimately prove a better choice). <No personal experience with that fixture> Would 150w MH + 250w MH represent a significantly bigger power expenditure than, say, 2 150w MH with 2 65w PC actinic supplementation? 400w MH vs. 300w MH + 130 w PC ? -- all this assuming that the 250w is even safe/feasible. <Seeing as amps=watts\voltage, you will be using less amperage with your new setup, thus saving you in kilowatt hours, at least a little bit. The 250 watt setup sounds fine if that's what you want to do, but if you don't plan on adding clams\SPS, might as well use 175's or 150's in ~15" of water> Any input and suggestions greatly appreciated, <Anytime> Al <M.Maddox> UV light and coral color Hi crew!!<Hello,> I have read on several WebPages that brilliant coral color is from the coral protecting itself from UV rays. From what I have read, there are 3 types of UV- one being filtered out by the atmosphere. The other 2 exist both in natural and artificial lighting. I have upgraded to 2x 250 watt HQI 10K Ushios. I use a piece of glass in my canopy to kill the UV light. Will the lack of UV light cause my newly acquired brilliant green, yellow, etc SPS corals to lose some of their color? If so, is there anyway to counteract this? Thank you, now and for the goldmine of info on your site. James <The glass is not enough to kill all the UV light that is being emitted on the corals. Some corals might experience a loss of some of their color. The best way to counter act this is to take the lids off the tank. Make sure your MH's are high enough not to get splashed by the water. Good Luck MikeB.> How much light is too much Hi Everyone I purchased a dual 250 watt metal halide kit for my 110 gal. show tank which is 31 in. tall. I got a great deal on a 157 gal tank and will be setting it up instead. This tank is only 24 in. tall, is the 250 watt 5500K setup too much for it? <No, it is not too much for the corals but I would change the bulbs to 10k instead of 5500k. 5500 is too much on the yellow side and you will get more algae growth in the tank.> In going to the new tank I will need to add 1 more light since the 110 was 4 ft long and the new tank is 7 ft long. Should I sell the 250 watt kit and go with a triple 175 watt? <Proper light coverage is best. I would recommend 3 MH bulbs or even 4 for a 7ft long tank.> Thanks Robert <No Prob. MikeB.>

48" DE HQI setup (Like Aquaspacelight setup) <Hello, MikeB here.> I currently have 55 gallon long reef tank for 4 years. My setup is of the following Since I have a question on light I will describe detail 2x ARO elect ballast with PFO pendant ICECAP 10k bulb and 2 x 54 watt T5 ATI Actinic bulbs they are all in my 10" high Canopy with 2 icecap fans.<Ok, sounds good.> Corals are growing fast and liked Icecap 10k bulbs but would like to add more blue so I am thinking about putting one more 150watt HQI in the middle (I have extra setup for one more 150watt HQI and do not want to buy 250watt setup) Putting 150watt in the middle is this bad idea? I know there is a fixture from Aquaspacelight 2 - 250 watt HQI Metal Halide with one single 150 watt 20K double ended metal halide mounted in the center.<No, not a bad idea, just put your higher light corals underneath the 150 watt bulb and your lower light corals to the outside of the tank.> I was thinking about putting 150watt HQI 20k Ushio in the middle with 2 x 150watt HQI 10k icecap and 2 x 54 watt ATI actinic bulbs. Any recommendation?<Uh, 450 watts on a short tank is a tremendous amount of light. It would make your tank look awkward in my opinion. I would take the 20K bulb and put it in the middle with one 10K on each side.> Tank: : 55gallon 48" length 13 deep TruVu Filtration: Custom build sump 30x 11 x 16 (small refugium mangroves with 27 watts 64k) Skimmer: AquaC Ev-90 Pump: Lifeguard 1140gph external pump Circulation: two 1/2 sea-swirl in the both comer attached to Lifeguard 1140gph pump one Rio SEIO 620 Overflow: CPR 102DX 1400gph in the middle Refugium: 10 gallon (20x10x16) custom made above tank refugium (CPR hang-on style) RIO 2100 from right side of main tank to drop left side of main tank Light: 2 x 150 watt HQI 10k for main tank 2 54 watt T5 actinic Chiller: CSL inline 1/4 HP Inline Chiller Live Rock: 80lbs Live sand: 70lbs in display tank and 20lbs in above tank refugium and 10lbs in sump. Corals: Ricordeas, mushrooms, buttons, sun polyps, leathers, brains, hammer, frogspawn, 2 squamosa, 3 maxima, 3 Crocea, Some SPS flags Chris Kim <Well you have enough filtration and I can see why the corals are doing so well. Again, I wouldn't concentrate the light on one area of the tank. Spread it out. MikeB.>

Re: 48" DE HQI setup (Like Aquaspacelight setup) Mike, thanks for your comment.<Sure, no problem.> I have current 2x 10k 150watt HQI located to cover 24" each and plan to put 1x 20k 150watt in the middle is this bad location? Or I should put evenly 3 HQI distance?<Do as you plan but you definitely want them even distance from each other. My pendant is about 9 inches so I have current setup like this 10"--- 9" (10k HQI) --- 10"---9" (10k HQI) --- 10" = 48" So my next setup was going to be 10"--- 9" (10k HQI) ---1"--- 9" (20k HQI)---1"---9" (10k HQI) --- 10" = 48" I currently have them about 6" from water (from water to HQI bulb not pendant end) should I raise little more? (Maybe I should so that middle 20k could cover more area...) Oh, also some people suggest actinic light 12 hours... So after setup I was thinking following: 11 hours 2x T5 54watts 9 hours 1x 20k HQI (middle) 8 hours 2x 10k HQI 13 hours light refugium. Could you tell me your opinion? < you want to go dark to light. So, when I would turn on the actinics first then the 20k then the 10k and when I turn them off I would go 10k to 20k to actinics. As far as length of photoperiod you have to determine that by the way your corals react. I would run the light on the refugium opposite of the tank.> Thanks <Good luck. MikeB>

Lighting, heat Thanks so much for your reply. I will do just that. Do you have any suggestions about the heat? My room temp is 72F. Not sure why I cannot get my heat down. Thanks!! <"green house effect", try removing one or both of the glass lids on the tank. Good Luck. MikeB>

Halides for a FOWLR I've read probably every one of your FAQ pages and articles on metal halide, lighting for a FOWLR tank, but still have a few questions. Do I definitely need a 72"hood for a 72" tank (180 gal, 24" deep)? << No way. You don't need a hood at all. In fact I kind of like the new trend of no canopy tanks. >> Is the fire/heat hazard situation, with adequate ventilation, enough to forego the use of metal halides? <> Do the good characteristics of VHO and compact fluorescent preclude the use of MH for this application ;cost considerations aside? << For fish only, I'd probably use a bunch of VHO bulbs. As you said you really don't need the halide lights if you don't plan to grow coral. I think it would be better to invest that extra money into a refugium or something along those lines. >> Thanks, Scooter << Blundell >>

Lighting Hi again...ask you something...about metal halides. Are the ones used for signboards by the free way the same as the one used for aquariums...thanks... >>>No<<< Metal Halides above water - 11/22/04 Hello, <Hey Brent!> I have a 55 gallon aquarium that I'd like to add metal halides. Since my canopy is 7 inches, about 6 inches off of the surface of the water, it seems through reading the FAQs that I'll have to build a custom canopy. Can you tell me how high the canopy should be? <Well it is more important to note how high the recommendation for halides to be above the surface of the water. I would suggest 7-10 inches above the water (minimum) and definitely incorporate a fan or two into the canopy for cooling and moving the trapped heat out of the canopy. Do search the internet (via Google, Dogpile, or Yahoo) for DIY canopies. See if there are any helpful DIY plans available. Good luck ~Paul) Thanks, -Brent

UV filter? Hi crew- This is a second thought to my last question. I am buying a DIY HQI system. They recommend (strongly) a UV filter. What should I use? <> James << Blundell >> Building your own metal halide system and canopy Hi crew, I hope all is well, and if its not, I hope it gets better. I just finished building my own canopy to house my metal halide system. It is built out of pine. My MH are complete DIY, with a reflector. Do 250 HQI's get hot enough to warrant some insulant between the reflectors and the wood( I spent hours making it, don't want it to turn to ashes just yet)? <> Is painting the inside of my canopy white sufficient to reflect light? << No way! For about $10 you can buy fantastic reflectors which make all the difference in the world. Best money you will spend on your tank. >> I also want to address everyone who asks a question to you guys. There is a donation area to keep these guys up and running. I figure about 1-2 dollars for every email you send to this site is more than worth it. The information is invaluable, and it will keep them here. I figure I have asked about 10 questions this year, so I'll be sending them $20. It is expensive to run a site, so let's all chip in!!! << Well that is awful nice of you. I think that is a little high, and I feel bad seeing you pay that much. I think $.02 is fine (like asking for my two cents on something). You know if you really want to, write in a question about advertising for a certain price (I have no idea how much) Cesnales will put an add for you on our site. We appreciate the donations, and we are here to help. >> Thank you crew. James P Rhode Island << Blundell >>

U.V.. risk using Sylvania Metalarc bulbs Hello there, I have a few questions to make about lighting. First some background data: I live in M?ico and here is hard to find (not to mention the high prices) bulbs for the reef tanks. I have purchased some XM bulbs from Marine Depot but last time had some trouble with the toll (they charged me 60% of the total value on taxes... OUCH!). <Dang governments!> Now I'm trying to use the materials I can find in the city. And since we are setting up a couple of tanks, the costs (as always ;-) matters. <Same everywhere> Now the question: I bought an Sylvania Metalarc halide 175W bulb (6500 K) in the past days, but I am concerned about the physical risk for using them. In the box says: "This lamp can cause serious skin burn and eye inflammation from short wave ultra-violet radiation if outer envelope is broken or punctured". I know it may sound silly, but I don't know what they mean with outer envelope... is it the glass? (I don't imagine a bulb with the glass broken working... hehehe). <Likely you are correct here... modern non-fluorescent U.V. lamps have a coating applied to their outer surface or an outer envelope of filtering glass (as opposed to older styles that aquarists used UV filters that were additions to, components of the fixtures themselves)> I have not found information about this in the Sylvania web page, so any help would be very appreciated. Finally, do you think this kind of bulbs might be useful for coral propagation? may be used for some particular species? Thank you very much for your time and advice. Best regards: Carlos M. Storch <Should be as long as the energy produced is of PAR (Photosynthetically Active Radiation) quality. You should look about on the Net, query the various specialty BBs (ReefCentral, Reefs.org) for input here. Bob Fenner> Sylvania Halide lights? Hello again, can you make a little correction in my FAQ, please?. I wrote "question" twice, so please put a couple of "q" instead c... << No problem, I got it. >> A little Spanish confusion... sorry! Thanks a lot and best regards. Carlos M. Storch Hello there, I have a few questions to make about lighting. First some background data: I live in M?ico and here is hard to find (not to mention the high prices) bulbs for the reef tanks. I have purchased some XM bulbs from Marine Depot but last time had some trouble with the toll (they charged me 60% of the total value on taxes... OUCH!). << Wow, that is high. >> Now I'm trying to use the materials I can find in the city. And since we are setting up a couple of tanks, the costs (as always ;-) matters. Now the question: I bought an Sylvania Metalarc halide 175W bulb (6500 K) in the past days, but I am concerned about the physical risk for using them. << They are fine to use, and will grow corals quickly. However, they don't make the corals colorful. >> In the box says: "This lamp can cause serious skin burn and eye inflammation from short wave ultra-violet radiation if outer envelope is broken or punctured". << Yes, I wouldn't worry about UV radiation with that bulb. >> I know it may sound silly, but I don't know what they mean with outer envelope... is it the glass? (I don't imagine a bulb with the glass broken working... hehehe). << Yes, they mean if you break the outer glass layer. >> I have not found information about this in the Sylvania web page, so any help would be very appreciated. Finally, do you think this kind of bulbs might be useful for coral propagation? may be used for some particular species? Thank you very much for your time and advice. << If you do use this, you will want to add a lot of blue actinic light to offset how yellow these lights are. >> Best regards: Carlos M. Storch << Blundell >>

50000 or 20000 Kelvin bulbs Hi! When you search the Internet you can find a lot of information about the 50 000K metal halide bulb made by Iwasaki. Iwasaki has also got a new 20 000K bulb with higher lumen output. Do you experts have any opinion of the performance (success/failure) and the looks of this bulb? <> How does it stand out compared with the 50 000K (the 50 000 seems to be considered "the best one" by many people)? <> I plan to have soft corals, mushrooms and buttons in my aquarium (150W/45 gallons). << In that case, I'd stick with 20000 K bulbs. >> Thank you. Anders << Blundell >> Re: lighting advice Hi crew- <Hello, MikeB here.> This makes 2 questions in one night, and I apologize.<Not a problem, that is what we are here for.> I have a 90 gal, currently with 356 watts of mixed day/actinic PC's. I'm upgrading to MH. I plan on keeping several SPS (Acropora), a few LPS, a Xenia, an anemone (bubble), generally mixed reef. I am torn between the following lights (both include carrying over my 96w PC with 6700/10k bulb): 2x400w CoralVue mogul 10K and 2x250w HQI Aqualine Buschke 13K. This is a sizable investment, and I want to make sure I make the best choice. As always, your advice and information is invaluable, and I cant thank you enough. James <James, both lighting systems are great fixtures to add to your reef tank. Either choice you make you can't go wrong. I suggest you go with the 250 W HQI metal halides because you indicated that you want a mixed reef. If you went with the 400's you would be supplying a little to much light for the LPS. If you wanted a SPS tank only then the 400 watt fixture would be the way to go. I would suggest that the 250 watt bulbs you try and get in 10,000 K output, 13,000 K is a little on the blue side. Remember your tank is 4 inches deeper than a 75 gallon tank so the lighting will be softer at the bottom. Good Luck!!! MikeB>

Halide UV shield Hi guys, how goes the battle? << Very well. >> I am up grading my lights from PCs to 2 X 250W 10,000K halides( still debating HQI or mogul), << HQI for sure. >> with 2 X 110 W VHO actinic. It will be a retrofit in a canopy, do I need any lens to protect my animals? <> Thanks, James RI << 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<<<

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 >> He Wants The Blues (20000k Blues, That Is!) Hello Crew, <Hi there! Scott F. here tonight> I have read quite a bit about this question on your site, which has lots of great information, but I am still unsure about this. I have a 110g (24"deep) tank with 2x250w 10,000k HQIs which are 2+ years old. I have BTA's and SPSs. I REALLY like the look of the 20,000k bulbs and thinking of switching. I read on your site that 10,000k is preferred for the BTA's. Does this mean that the BTA's would really have a problem?? <Well, I don't think that they'd have a "problem", but I think that your anemone's would grow faster and generally do better under a more full-spectrum light...I am a huge fan of 20k's, myself, but the majority of 'em just don't carry the same "punch" as 10k's. However, I simply love them! They are still excellent bulbs, and will do a nice job with many corals and inverts, rendering excellent colors, albeit with slightly slower growth. Just understand their limitations and change them out regularly> Like I said I love the blue look. I have heard the SPSs would be OK. If it is cool to switch do you have a preferred brand (XM MegaChrome, etc.) and what would you recommend for acclimation of the new 20k's. Thanks, Rich <Well, my personal favorite brands of 20ks are Aqualine Buschke, Geissmann Megachrome, and Helios. Icecap is releasing a 20k bulb soon which seems really promising. Acclimation to these bulbs would be best conducted slowly, perhaps using the window screen technique, whereby you cover the area under the lights with a few layers of window screen, and gradually remove them as your animals acclimate. Good luck! Regards, Scott F.>

Shrimp breeding and halide lights Greetings Crew! << Blundell here today. >> I just can't say this enough, but thanks for putting up such a great site! I love reading the daily FAQ's and surfing through the archives. Got two questions for you today. 1. I have a 55-gal reef system (corals, fish, inverts, etc.) and I have one red skunk cleaner shrimp. Today I noticed that he is actually a she as her belly is full of what I can only assume to be eggs!!!! Now, I lined up the suspects in the tank and the only ones I can come close to thinking of are my pair of Fire Shrimp (one of which had eggs last week). Is it possible for a fire shrimp and skunk cleaner to mate? <> Or will shrimp produce eggs in absence of a mate and just hope they get "lucky"? <> The only other suspect would be my Coral Beauty, but I think his love affair with my cleaner is just related to the cleanings! << Agreed, at this point I'd be suspect, but potential cross breeding may actually be taking place. >> 2. This is relating to metal halide bulbs. I am totally familiar with wattage and degrees Kelvin (planning to construct a custom oak suspended canopy with 2x250W of MH). I have a friend who works in an industrial supply company and they have hundreds of different MH bulbs in stock. The problem is that the bulbs are rated in Lumens and color temp. Is color temp the same as degrees K? << Yes, that basically means what colors of light are being given off. In other words how much of the light is red, how much of it is blue and so forth. >> What are Lumens? << Lumens is how much total light is given off. For instance you can have a very blue bulb that gives off only blue light. But that light may be very dim like a moon light (low lumens) or it may be very bright like a search light (high lumens). >> Is there a way to compare these bulbs with those used in the aquarium industry or am I comparing apples and oranges? << Well with a PAR meter you can really compare bulbs well. But for the average hobbyist I think that comparing visual colors to you, and also Kelvin ratings is good enough. >> Thanks again and have a happy Halloween! -Ray << Blundell >>

What Kelvin rating to use I have a 200 gal tank, 72" long. For my light fixtures I have a Coral Life MH Fixture that Holds 2 175w MH and 2 48" Fluorescents, then I also have 2 additional MH fixtures that will hold 175w MH. So in total I have the Ability to have 4 MH and 2 48" Fluorescents. In this tank I am wanting to have probably Mushrooms, Polyps, Leathers, and things like this. I am going to have some were around 200-300 lbs live rock. Is my lighting sufficient or too much, and what kind of MH bulbs should I put in my fixtures, 10,000 k, 50/50, ???. << All sounds good. I'd run 10k or maybe 14k halides. I'd run some URI actinic for your fluorescents. >> Thanks much for all the answers you can give. John M. << Blundell >> Lighting hardware recommendations 10/28/04 Hello Sir Calfo, <no need for the formality, my friend... certainly not "sir" - I work for a living <G>.> I just had some quick questions about MH lighting. Do you have a preferences between the PFO or Ice Cap digital ballasts? <I have no preference based on performance. At best... I lean towards Icecap based on a few studies/comparisons I've seen (see the coming article in Reefkeeping magazine... Nov. 04 I think... by Joe Burgher comparing ballasts and lamps. That all said, I do favor IceCap for their customer service which has been stellar from the very first day they hit the market> I want to use a 400w 10,000k Ushio. I've read that you can only use HQI bulbs with the PFO's?? The Ice Caps can take standard and HQI bulbs. If the PFOs can take a standard bulb could you give me an opinion on which one works better? I've very much so enjoyed your BOCP and Reef Inverts. <thanks kindly> I'd like you know if you two are in the works for the next addition of the Natural Series? <why, yes... thanks for asking :) I am going over a final first pass of the bulk of content for the work... and it will be in the layout editors hands in days/weeks. Targeting a release of early next year for part 1 of 2 for the Reef Fishes volume> I'll be looking forward to it if you guys are:) Thanks a million Chris AKA ~fishtank~ <looking forward to it too, my friend. Best regards, Anthony>

250 or 400 watt halides? Gentlemen, << Kevin. >> I have been reading all of the FAQs on your wonderful site, as well as reading quite a few books and I think I have gotten myself into a situation where I have too much information to make up my mind about a few things. << That is far better than having too little information. >> My setup is as follows: 220 gallon tank (72x24x30) Lighting is currently 3x250 20K Radium halides and 2x160 VHO Actinics PH 8.2, SG 1.024, Temp 77-79, ALK 9.6 (Salifert), Calc 420 (Salifert), Ammonia/Nitrite/Nitrate/Phosphate all 0 I have 220 lbs Live Fiji rock that goes about halfway up the tank, but set in the middle of the tank to allow space behind for cleaning Currently I have a number of SPS Frags (Acros & Montipora) and a colony of Pocillopora that I moved over from my 90 gallon tank 2 Euro-Reef ES 5-2 skimmers Return pump pushes about 1500gph through 2 SeaSwirls, 3 Maxi jet powerheads, and 2 Seio?) 620 GPH powerheads for circulation. Tank is about 8 months old (corals added about 2 months ago) Lights about 6-7 inches off the water Now to my questions: 1. Everyone around here, including my LFS is telling me that I need to move up to 400W halides. << Before doing that, I'd probably move to 10k or 14k bulbs. >> I am seeing growth in 90% of my corals (One coral has grown about 1/2" and started three branches in the two months its been in the tank) and coloration is good (feed phytoplankton and zooplankton). Because my rockwork only covers half of the tank I am concerned about putting corals near the bottom. Also, would like to add clams at some time and am concerned for there well being. << Keep the clams up high. >> I don't mind investing to do this, but am not sure that I really need to. << I'm not sure if you need to either. I think moving to a 10k bulb will do just as much good, coming from the 20k bulbs. >> Mainly I am concerned about the long-term well being of my corals. The more I read on the web the more conflicting information I get and can't make up my mind. Any suggestions? << You can't have too much light.... but you may not need any more. >> 2. Should I upgrade/add a new skimmer. I am getting plenty of stinky results from my Euro-reefs, but their "rating" for tank size has seemed to drop since I bought them. << Well a bigger skimmer is always great. But I'd check out lighting options over skimmer options first. >> I appreciate your input. Thanks for your help in advance, Kevin Miklausich Raleigh, NC P.S. Sorry for the length of this email. << It's okay, we get lots of long emails. >> << Blundell >> Lights for a 5ft tank hi << Hi there. >> I have a 5ft, 70 cm deep marine tank and I was wondering what would be the best MH for my tank (Kelvin, watts and how many) also I would like to keeps anemones and soft corals << I'm unsure if you meant 5ft deep or 5ft long. Anyway the depth of the tank is the most important factor for this. I'll assume your tang is 70cm deep. I'd probably go with two 250 watt halides, and also a couple VHO bulbs for actinic light. Hope that helps. >> thanks << Blundell >>

Wattage and Kelvin rating So what would be the best lighting only in MH for my 5ft L by 70cm H << I would probably go with two (or three) metal halide bulbs. Each bulb being 250 watts, 14k bulbs. That is ideal for me. That opinion will change as new products come out, but for now that is what I would use. >> (KELVIN AND WATTS) << Blundell >>

Higher "K" rating MH lighting Hi crews, A quick one here (hopefully). I am running a 10000K 150W DE MH pendant on my 33 gallons (24"x18"'x18", 5" sand bed) and is hung 11" above water surface, water depth is thus about 12". Do I have enough to keep the most light demanding creature on sand bed? I am thinking of changing to 20000K but afraid that it is not going to have enough PAR for the most demanding SPS or clam, as it seems that 20000K's PAR is about 1/3 of 10000K's of the same wattage. What do you think? What if I supplement with 2x55w day light PC? And what about 14000K bulb? Which seems to be about seems that 20000K's PAR is about 1/2 of 10000K's of the same wattage. What if I supplement with 1x55w light PC? Thank you very much for your time and effort. Best regards, Wid >>>Greetings, If the water depth is only 12", then you're doing pretty well with a 150W DE setup. However even then I wouldn't say you can keep ANYTHING - at least if you want the coral retain it's color. By this I mean some of the more demanding Acros out there. ALL clams will be fine. I find the 20k's MUCH nicer to look at, and they give much better color rendition. I just switched from 10k's (250W DE's) to 20k's a few months ago and couldn't be happier. Yes, you will lose a bit of intensity with the 20k's. Sure, you can supplement and increase the total PAR. I would stick with the single 150W DE, get a 20k bulb and be done with it. There are plenty of nice corals you can keep, not to mention the clams. With a 33 gallon tank, your limited anyway as to how many corals you can keep. I have no experience with the 14000K bulbs. Cheers Jim<<<

Higher "K" rating MH lighting - Part 2 Hi Jim, Thanks for your swift response as always! Went to LFS just now and looked at Iwasaki 20000K 150W DE, it is so white, only with a slightest hint of blue! And the LFS owner said that BLV will be just a tad bluer. I guess it all depends on ballast. If a 20000K bulb appears whiter, does it mean that it will have relatively more PAR than its bluer appearance counter part? I just got a good deal from someone selling his 70W DE MH, I am planning to run a bluer 20000K 150W bulb for 10 hours a day and run the 70W on an industrial bulb (5000K-8000K depending on the bulb I am getting) to supplement the red and green range for 5 hours a day to simulate noon sun. How does this sound to you? Thanks again. Wid >>>Hey Wid, All I can say is try it and see how you like the effect. The organisms don't require that you attempt to simulate 'noon' with a different color temp however. If it were me, I'd use the extra fixture to increase the total PAR on the tank for the entire duration of the light cycle.

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