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FAQs about Coral et al. Cnidarians System Lighting: Lamps, Bulbs

Related Articles: Coral Lighting: what we know and what we don't know (mostly the latter) by Sara Mavinkurve
Lighting Reef Systems: Considerations, Organisms, Goals and Costs by Bob Fenner Light/Lighting For Marine Systems, Coral Feeding, LPS Corals, True or Stony Corals, Order Scleractinia, Propagation for Marine Aquarium Use

Related FAQs: Coral Lighting 1, Coral Lighting 2, Coral Lighting 3, Coral Lighting 4, & FAQs on Coral Lighting: Science/Application, Designs/Fixtures, Quality, Duration & Intensity, Night-Time, Troubleshooting/Fixing, Makes/Models/Manufacturers, & Lighting Marine Inverts 1, Lighting Marine Inverts 2, Lighting Marine Inverts 3, Lighting Marine Inverts 4, Lighting Marine Inverts 5, Lighting Marine Inverts 6, & LR Lighting, Fluorescent Light 1, Actinic Lighting, Compact Fluorescents, Metal Halide Lighting, Lighting Marine Invertebrates Growing Reef CoralsStony Coral IdentificationStony Coral Behavior,

Much to investigate to discern what's available, and the "better/best" fit for your needs... Do know that there is quite a difference between lamp makers, and their too-many relabelers... DO look for input from reliable sources (e.g. Sanjay Joshi, Dana Riddle) and take into account as much hobbyist (BB) input as you can stomach, before making the short and long-term (electrical) investment.

Small Marine Aquariums
Book 1: Invertebrates, Algae
New Print and eBook on Amazon:
by Robert (Bob) Fenner
Small Marine Aquariums
ook 2: Fishes
New Print and eBook on Amazon: by Robert (Bob) Fenner
Small Marine Aquariums Book 3: Systems
New Print and eBook on Amazon:
by Robert (Bob) Fenner

Stony corals... sys.     2/24/13
Hello Mr. Bob.
Took my time on WWM and found answers for stony corals , so I have to thank you for that and also for all the new things I have read. Found also some really useful info about fire worm!! Still need a way to kill it though.
Tried the trap thing but unsuccessfully. I hope that I will come up with something.
Right now I need your personal opinion on lighting as it concerns stony corals.
What do you prefer?? LED , T5 , T8 or MH ?? I am thinking of going from T8 to LED.
<If you can afford the initial cost/investment, LED... then in order (for shallow (24 inches or less water depth), T5, 8, then MH for function>
Also I read many FAQ's at WWM , 6500K is better for growth but coral lose color , 12000-14000K is a middle situation and 20000K is best for coloration. Do you support that??
<Not really; no. The 6,500K is best, most realistic... but "beauty is in the eye of the beholder"... is mostly subjective>
 And here are my thought and need once again your opinion. I am thinking of building a new tank only for stony corals (after what I have read about soft and hard corals in same tank :):):) ) and thought of the following about the lighting. Instead of 14000K permanently I thought of using 6500K for some time (let's say 2 weeks or month) and then use 20000K for the same time , so the corals can grow fast under 6500K for the specified time and then take their colors under 20000K for the same time. Do you believe that this can work??
 If yes how many days/weeks/months under 6500K and how many under 20000K do you suggest???
<Leave the 6500K on permanently>
 Or would be better to leave them under 14000K permanently and will have better results???
Now I am after iodine (that I know nothing about) and then let you know with my questions (if there are) !!
<Cheers, Bob Fenner>
Thank you once again for your precious time.
Best regards

65 Gallon Set-Up, Reef     5/17/11
Hello Crew,
This is my first time writing in although I have referred to your site many times with my many random ideas & questions. My reason for writing you today is twofold. First, I would like to share with you the hardware that I have picked out to set up my system & see if there is anything that I missed along the way & if there are anymore suggestions you'd like to offer. Second, (I'll probably include this in a follow up email after your reply) I would like to get your opinions & help on some stocking suggestions for my tank. I plan on doing a Philippine Reef Biotope. I have some ideas that I'd like to get a second opinion on. I'm the only one of my friends/family that is into this hobby so a sounding board would be nice.
So, a little background ... I started my marine addiction with a 29 gallon tank, but quickly realized it would not house anything I was truly passionate about keeping & the animals always come first in my book, so I was not about to try my luck with overcrowding a small tank. I have since turned my 29 gallon into a custom sump/fuge & upgraded my display tank to a "Reef Ready" 65 gallon. My equipment is as follows: 2x Vortech MPw10wES/AquaC EV-120 powered by a Maxi-Jet Utility 3000/2x BRS reactors for carbon & GFO each powered by Maxi-Jet 900/Return pump is another Maxi-Jet Utility 3000. I am using a JBJ TrueTemp Digital Controller with a 500W Finnex Titanium Heater Element. The element sits in the return portion of the sump & the remote temperature probe is in the display tank.
The fuge contains a DSB of about 7" of oolitic sand & is lit by 2 5000*K spiral bulbs on a reverse light cycle.
<Mmm, don't "turn on" the GFO reactor till you have a reason to. Will otherwise deprive chemoautotrophs of nutrients>
Finally, my lighting for my display tank is where I have the most freedom to change things. I purchased the 36" AquaticLife T5HO fixture of the 4 bulb variety. (Wishing I had gone with 6 now) The fixture came with 2 "actinic" bulbs
<Trade at least one of these out for more "white">
& 2 10k bulbs & also has the moonlight LED feature with built in timers.
Now the all important lighting question(s). I would like to upgrade my bulbs to a combination of 2 Giesemann Aquablue+ bulbs
& 2 UVL AquaSun 10K bulbs. After researching rather extensively I do not feel it necessary to incorporate any "actinic" only bulbs.
<This is so>
I would rather put my 4 bulbs to better use! Do you feel this is a viable lighting combination?
<Can, could be>
If not, what would you change if it were over YOUR tank?
<As stated above>
I plan on keeping a few Acropora & other SPS corals, a few softies & even some display macroalgae. All indigenous to the Philippine Islands as I am striving to recreate a biotope to the best of my ability.
Here's where it gets fun! :) There are 3 timers built into the fixture.
One controls the moonlight LEDs, another controls the bulbs in positions 1 & 3, (currently actinic) & the final timer controls the bulbs in position 2 & 4 (currently 10k.) The default program that comes on the light fixture is 10 hrs: moonlight - 1 hr: complete dark - 1 hr: actinic only - 10 hrs: actinic & 10k - 1 hr: actinic only - 1 hr: complete dark - back to the moonlights. Is this lighting schedule sufficient?
When I upgrade the bulbs would you suggest any changes to the schedule?
<Just as stated>
Finally, what bulbs would you place in positions 1 & 3/2 & 4?
<Either 1 or 3 as the only "blue">
Bulbs 1 & 3 come on first followed by bulbs 2 & 4. I was thinking the Aquablue+ bulbs should come on first followed by the 10k bulbs but I have thought about it until my brain hurt. That's why I'm emailing the experts.
<This is what I would do>
Thank you in advance for taking out the time to help a fellow hobbyist.
Hope I didn't make it too confusing for you.
<Not at all. Cheers, Bob Fenner>
Re: 65 Gallon Set-Up, lambda, P.I. stkg.    5/21/11

Thank you so much for your reply. I will take your advice on the lighting scheme & use a 3:1 white to actinic ratio on my light fixture.
<Is what I would do... or skip the actinic/s altogether... use part of the time, intensity of the Moonlight LEDs you mentioned last for the "blue" colouring, beginning and end of daylight times>
As mentioned in my previous email, I am currently finalizing my plans for my Philippine Reef Biotope & would like you to have a look over my proposed stocking list. I have always been a fan of commensal relationships that can be portrayed in the home aquarium setting & plan to display this in a few areas in my tank. As always your thoughts & advice are welcome. After all, that's what I'm here for!
65G Reef Ready w/ 29G Sump/Fuge
-Amphiprion ocellaris (currently have 1 juvenile from a local breeder)
-Chromis viridis (I would like multiple specimens of this Chromis for overall tank movement. How many would you suggest?)
<In this volume, just 3 or 5 if they're small>
-Oxycirrhites typus
-Stonogobiops nematodes
-Synchiropus picturatus (ORA Tank Bred specimen only)
-Lysmata amboinensis
-Lysmata wurdemanni
<? From the Atlantic; I'd likely skip>
-Alpheus randalli (to pair with Stonogobiops nematodes)
-Entacmaea quadricolor (hopefully my tank bred ocellaris will accept it. I have a local source for aquacultured specimens)
-Various Acropora corals & other SPS corals with commensal crabs.
-Some type of red gorgonian to make the Longonse Hawkfish feel at home I realize that housing BTA's & SPS's in the same system isn't usually advised, but I'm hoping the minimalist approach I will be taking with the aquascape will give them plenty of separation. I'm also hoping that the fact that the BTA will be an aquacultured specimen will help greatly with it being happy in the tank & not moving around. Any thoughts or suggestions on the stocking list would be greatly appreciated. I'm trying to iron out the last few details before I continue.
<Acclimate the Anemone through water interchanges while it is in captivity (or the SPS alternatively)... You've read re such methods for reducing the intensity of Cnidarian allelopathy?>
One small request, I noticed on the Biotope FAQs on WWM that Scott F is quite the biotope specialist & self proclaimed biotope geek. Is there any way I could get an email to contact him directly with some of my more menial questions that I would rather not bore you with? :)
<I will cc ScottF here; he's become very busy in recent years... but will likely see something sent to him directly>
Thanks in advance. Enjoy your weekend!
<Am down in Costa Rica for a couple weeks, surfing and diving... Oh yes, very enjoyable. Cheers, BF>

Reef Lighting 12/6/10
Hey everyone how are we today?
<All is well, Matt>
I hope well. I got a question about bulb configuration on my 26 gallon bowfront. I have the Current
Sundial 4 24w T5 bulb light fixture. I briefly tell you what's in the tank and what bulbs I've had and thinking about getting and trying.
Top half the tank is few med size Acros and several small to large Montiporas and couple lps and lots of Zoas. Bottom half the tank is mainly few large lps and lots of Zoas and mushrooms. Ok in the past I
have used two different sets of bulbs, the first was one UVL 75/25 and dd
<?> <<D and D, UK distributor>>
Geismann "1100k"ish bulb ( forgot the exact name) and two 460nm blue acintics (actinics>. The second setup was that same dd Geismann bulb and an ATI Aquablue (1400k) and two UVL super acintics (420 nm). And now I was thinking of going with one 6500k and one super acintic <actinic> and two blue
460nm acintics <actinics>. So my question is, and sorry for dragging it out, is would the bulb config<uration> I'm considering be enough light or should I stay with two daylight bulbs like in the past? Thanks for your time!
<To make the most out of your available photosynthetic energy, I would use no more than one actinic
tube with the other three being in the 10-12K range. Four UVL Aquasun tubes will provide a nice looking display as well as providing a good nanometer range of useful light for your corals. James (Salty Dog)>

2 Lighting questions   9/19/10
Hello all,
<Hello James>
I hope everyone is well.
<Yes, thank you!>
I have 2 quick lighting questions.
1. I have a 55 gallon tank with a 4X65 watt PC fixture. It currently has 4 50/50 bulbs. My corals include Ricordea, xenia, star polyps and a few mushrooms. From a health of my coral perspective are the 50/50s ok or would they be better under different lamps? Perhaps 4 10000k lights.
<I would go three at 10,000K and one actinic here, or two at 10,000K and two 50/50>
2. I added another refugium for macro algae growth. I have had 2 lights recommended to me for it. First a 24" florescent grow light or a 75 watt CFL flood light with a 5000k rating. Both cost about $10 and are available at local home or hardware stores. What are your thoughts on these for macro growth.
<Difficult to say without knowing more about the 'grow light', but with the lack of this data I would veer towards it. I have tried growing macros with domestic 5000K bulbs, and had far better results when using 10,000K. If you can get anything over 6500K you're onto a winner. There are a few good smaller units (try Solaris) that will do a better job than cheap versions you can get in the DIY stores>
Thank you again for your help,
<No worries>

Lighting Questions (livestock selection, Kelvin vs. PAR, etc.) -- 08/04/10
Hello -- hope you love your job -- 'cause I've got questions!
<<We are pleased to be of assistance>>
I have a 125g display tank in which I'd like to keep some SPS corals.
<<Okay--and a descriptor (SPS) that can prove rather ambiguous when trying to determine environmental requirements>>
I now have a CR <<Calcium Reactor>> and keep the KH at 9 or 10 and CA between 420 and 440 day in and day out. Now, I want to ensure my lighting is sufficient. I realize not all SPS require the same lighting
<<Indeed--though many/most prove to be very adaptive in their 'requirements.' But much of the time these 'requirements' are more for the coral 'keeper' rather than the coral itself. For instance, the 'requirement' for a coral to produce bright color is not necessarily a 'requirement' for the coral to live'¦or even to thrive>>
-- but perhaps you could recommend some that will thrive with my lighting: 3x150w MH + 4x96 Dual-Actinics (Outer Orbit fixture). The light is about 6" from the surface of the water.
<<The Kelvin or 'color' temperature of the bulb can/will have a large impact. A lower Kelvin will generally produce a higher PAR (given bulbs of the same wattage and similar lumens). Reading ahead I see you are using 20K bulbs. At 150-watts, on this system, I think these will limit your ability to keep some of the higher-light loving Acroporids'¦not that you can't keep them alive, just that they won't be as 'spectacular,' as indicated earlier. 'Green' Pocilloporids and Montipora will probably do fine, but the 'pinks' likely won't color-up too well unless 'very high' in the water column, if even then'¦nor will the 'German Blue' M. digitata. I suggest you either increase the wattage of the MH fixture--or more simply--reduce the Kelvin temperature of the bulbs (10K would be my choice here)>>
I also was wondering if there is a correlation between Kelvin and PAR?
<<Indeed there is'¦ Among bulbs of the same wattage'¦lower Kelvin = higher PAR>>
By the way, I have not measured the PAR value in my tank -- I hope to do so in the next week if my local reef club will loan me a PAR meter. I currently run 20K MH bulbs and have been thinking of trying some 14K bulbs next.
<<A good solution--but I feel a change to 10K (for what you are aiming) would be best>>
I do replace them every 12 months.
Thanks for your time to reply,
<<Happy to share'¦ EricR>>

R6: Reef Setup Critique -- 06/13/10
It's been a couple hours since I have emailed you guys so I guess it's time to bug you again.
<<No worries Mike>>
Onto the lighting...the tank has a canopy with 2 VHO's (I'm going to run actinics on this) and 3 mogul sockets for 400W metal halides.
<<I hope there is some means of venting air/heat from this canopy>>
What brand bulbs do you guys like?
<<Often, what you pay for is what you get'¦ Some bulbs worth looking at include offerings from Ushio, Hamilton, Phoenix and Aqualine-Buschke (not necessarily in that order). I'm currently trying out the CoralVue ReefLux 10K bulb and thus far consider this my fave among 10K bulbs'¦but it is still early in the testing>>
Being that I have actinics would you recommend 14k or 10k?
<<A multitude of factors at play here (do peruse WWM re), not the least of which is the planned stocking of this system. Generally my preference would be 10K'¦more natural appearance, better PAR/penetration'¦but if this tank is not going to house 'high light requiring organisms' the 400w 10K may prove to be too much; considering the close proximity of the bulbs to the water's surface determined/limited by the use of the canopy, in which case 'less potent 14K bulbs' may prove more appropriate for the organisms being kept>>
<<Happy to share'¦ EricR>>

Lighting Causing My Coral Issues?/Reef Lighting 5/27/10
Hello crew!
<Hello Heidi>
I'm really having an issue in my tank and have asked on many different forums and not getting much help. So I'm turning to you for your expertise.
<We'll do our best to help you.>
I currently have a 75 gallon 48"x18"x21" tank with a 30 gallon sump/fuge. Eheim 1260 return pump, Koralia 3, Vortech MP40, AC jr. controller, Bubble King 160 skimmer and Phosban 150 reactor for carbon/Phosban. I purchased a light fixture that was used for 1 month. I'm not sure if I can mention the vendor name of the fixture but it is a 48" 6 bulb T5 fixture with 2 Ice Cap ballasts. It also has 2 LED's for moonlights. The light has been on the tank since the beginning of the tank which is almost 4 months old now. The bulbs consist of an ATI Aquablue special, IC <Ice Cap> Deepwater, IC Twilight, Geissmann Aquablue, IC Twilight, IC Twilight and are 2 months old.
The vendor states you can put the fixture right on the tank but they do have small leg brackets that you can buy which I did. They lift if off the tank about 2 inches. My first corals were a Hammer, Torch, candy cane, Purple people eater Palys, and multiple other Zoanthids.
I started them out at the bottom of the tank and after a week put the Zoanthids up higher and the candy cane mid tank. All of the corals except the candy cane turned very pale within that week. The Torch coral would expel it's zooxanthellae regularly. But it was already on the bottom of the tank. My lighting schedule at that time was dusk/
dawn 9am-8pm and the main lights were on from 1pm-7pm. I then raised my light by suspending it so it was 10 inches above the water and decreased the main light to 2pm-5pm. I also emailed the vendor of the light. They said all I was doing by raising the light was lighting the room. And that they had a 7 bulb fixture of theirs over a 55
gallon tank with softies such as mushrooms, leathers and Zoas at midlevel that were fine. She said that fixture was equivalent to a 400w metal halide fixture.
<I don't know if I'd go that far, perhaps closer to a 250w halide.>
I then purchased a couple more frags of Zoanthids after specifically emailing the coral vendor to ask what lighting they used. I told them what light fixture I had and they said the Zoa's prefer high light and didn't see any issue. They used 400w MH bulbs. I purchased them and placed them at the bottom to acclimate. Within a few days one of the
frags was turning pale. I emailed the vendor who thought they needed to be placed higher and were losing their color because they were too low. I placed the frag higher which didn't help. The only color that is left on that frag is a very light pink near the mouth. The rest of it is almost opaque white. Last but not least is a yellow scroll coral that I placed at the bottom and then moved to midlevel. It too seemed to lose quite a bit of it's yellow color.
So you get my drift here. The kicker is that the candy cane coral which has been in the same place since day 1 is fine. No color loss, growing and eating fine.
<Doesn't require as much light as the Hammer Coral.>
It is mounted midlevel. Hammer coral has had some color return. Also, all my parameters are good. Ammonia,
nitrite, nitrate 0. dKH 9, Calcium 420, Magnesium 1500 (to keep Bryopsis away).
<I'd get this back down to the norm, 1200-1300ppm. High magnesium levels can/could cause other problems.>
Temp 79 and salinity 1.025 by refractometer.
I hope I've given you ever bit of information I know.
<Was curious as to your water changing schedule.>
Is this just the light fixture? Too intense for soft corals?
<No, not too intense at all. Problem I see is that you have three lamps that are literally wasting energy. The three Ice Cap Twilights you are using are near pure actinic and peak out at around 425nm, and using three of them limits your useful or more desirable light for photosynthesis. One for color is fine provided the other lamps are in the
10-12K range. The other three lamps you have are two 12K's and one 14K.
These alone should give you decent color. I would replace at least two of the Ice Cap Twilights with lamps in the 10-12K range and you will greatly increase your useful light energy for photosynthesis. See Ice Cap's chart here. Note the difference in light energy spread out across the useful spectrum in the 12K lamp versus the Twilight Lamp. http://icecapinc.com/t5-lamps>
I've always wanted to try some SPS and was happy to have this fixture knowing it would support that.
<It should with proper lamp selection. Keep in mind that most corals we keep come from shallow water where the Kelvin temperature is higher.>
But not at the expense of being able to have anything else. I've had another T5 fixture over a 90 gallon tank and never had any issues like this. I'm really frustrated and was even considering changing light fixtures. Guess it goes to show you that more expensive isn't always better...
<You have a good system with the Ice Cap ballasts. They actually overdrive the lamps to a higher intensity than the norm.>
I appreciate any light you can shed on this problem. (Thank you...I'll be here all week) ;)
<Me too. James (Salty Dog)>

T5 Light Suggestion/Reef Lighting/Selection 12/8/09
<Hello Junaid>
Hope you are doing well.
<Yep, still above ground and walking.>
I currently have a 90 gallon saltwater tank with mostly LPS corals and looking into adding SPS corals in the future. I am running a Current Nova Extreme Lighting Fixture. I am going to be changing the light bulbs that came with the lights and looking into URI which seems like the best choice for price and from the forums I have read. I am still hazy in deciding which exact bulbs to get. My lighting fixture can hold 8 bulbs. This is what I am looking into:
54W T5 Actinic White Bulb (50% Actinic 03 & 50% tri-band phosphor adds color enhancements, 12,000k) x 4 54W T5 75.25 Fluorescent Bulb (75% Actinic 03 and 25% Tri-band phosphor, 14,000k) x 3 54W T5 454 Fluorescent Bulb x 1 (85% Tri-band ultra blue spectrum, 15% actinic spectrum) x 1
From previous posts I have read, Steve Pro has recommended getting two Actinic 03's, one white actinic 50/50 and one AuqaSun for lighting fixtures which can house 4 lights.
<Mmm, likely dated information. Too much actinic wastes light intensity of the other colors in the spectrum needed by most light loving invertebrates.
There will always be actinic (440-460nm) present in all lamps designed for our needs.
The lower Kelvin temperature lamps do not appear blue because the color is masked by the higher intensity of the other colors our shallow water corals also require. Spectral lighting charts will show this. Scroll down
on this link. http://www.ushio.com/products/petcare/aqualite.htm>
What would you recommend for my light fixture which houses 8 T5 bulbs?
Should I replace any of these choices with the AquaSun?
<If it were me, I'd go with seven 10 or 12K lamps and one actinic. This would still give you some nice color and still provide a high intensity output.
My choice in T5 lamps would be URI or Ice Cap.>
And what is the difference between T5 75.25 Fluorescent and T5 454 Fluorescent?
<The T5 75.25 is 75% Actinic 03 & 25% Tri-band phosphors. The T5 454 indicates the lamps
spectral output is 454nm.>
Thanks for your help in advance!
<You're welcome. James (Salty Dog)>
Kind Regards,
M. Junaid Shaikh 

Basic Coral Lighting 06/04/09
Hello Crew!
Thank you in advance for taking my question(s).
I have a standard 55gal saltwater tank. It is a reef tank with a pair of Clowns and a tang. I have a couple corals with polyps and mushrooms growing. I have dual 65 watt 21in fluorescents going.
1. What is the BEST lighting to go with - 10,000K, 6,700K, 50/50, or straight Blue Actinic?
<If these mushrooms are the only corals you plan to keep, any of the above should be fine. They're very adaptable. For what it's worth, natural sunlight is somewhere around 5000K.>
2. How often should you switch out bulbs?
<every 6 months or so>
3. Is the Coralife bulb line a better quality product than say, Current USA?
<In my opinion, no, not significantly.>
Again, this is just rule of thumb questions.
<If you're interested in specific coral lighting needs, you could start here:
But that's just to give you/people a very rough idea. There is so, so much debate about coral lighting... it's almost intimidating how many different methods/opinions there are out there about this subject.>
Thank you again!
<De nada>
Shawn Rivera
Sara M.>

Re: Power Filters ATTN Minh, plus now fluorescent tubes, circ. for cnidarians    1/14/09 Minh, <Hello John.> So now you are fairly familiar with my system and you had asked about my fluorescent tubes. Well lets just suffice it to say that once before I had a reef tank and decided to upgrade the lighting already. I purchased a 260 watt PC fixture. It comes with the usual arrangement of 2 10K Kelvin lamps and 2 Actinic lamps. Thinking of replacing the actinics with 10K Kelvin lamps. <Congratulations on the purchase.> I know this is not enough light for SPS or clams or many anemones but I would like to keep some soft coral like the toadstool. Perhaps an LPS like a frogspawn. <Although some Acroporids may actually need higher intensity illumination, Power Compacts may be sufficient for Montiporas and LPS if creative aquascaping and coral placement is utilized.> I realize that keeping a shrimp with a frogspawn is dangerous so I would not do it. <Shrimps in the Lysmata family such as Scarlet Skunk Cleaner Shrimp (L. amboinensis), Peppermint Shrimp (L. wurdemanni) and Blood Red Fire Shrimp (L. debelius) are opportunistic scavengers and may damage coral flesh when going after uneaten food in the coral's oral disc. Likewise, hermit crabs in the Calcinus <sic> family or crabs in the Mithrax <sic> family can also do similar damage. Coral Banded Shrimp (Stenopus hispidus) and "Yellow" or "Dwarf" version (Stenopus scutellatus) have less of a tendency to do so. Although all of these species have been housed in many tanks with Euphyllia without issues, keep in mind of the possibility of damage.> Also to let you know I purchased an Eheim 2026 and that should be here next week. So much for FOWLR. Once you cross over into a reef tanks there is no going back I guess! <It is an excellent filter, I suspect you will be happy with it.> My only concern now is will 2 Koralia 1's provide enough circulation for corals that may require I higher flow. I am sure they are fine for most leathers, the mushroom, polyps, etc. I just have no experience with Koralias. < The Hydor Koralia is from the new generation of low-cost propeller driven pumps that is quite different to the powerheads and pumps you've used in the past. Instead of generating a forceful jet of water flow, its large prop and shroud design allows for a gentle wave pattern that is much more efficient at moving water than a traditional impeller driven pump. The two Koralia 1's and the flow from the Eheim 2026 should be sufficient for most of the corals you intend to keep. Gorgonians are the exception as these requite more flow but with creative aquascaping and placing the specimen closer to the powerheads, you can work around the issue. For an excellent read on efficient flow design in a reef tank, take a look at this article: "Water Flow is More Important for Corals Than Light" (http://www.advancedaquarist.com/2006/6/aafeature2).> Thanks again Minh. I have really enjoyed communicating with you. John <You're welcome. Cheers, Minh Huynh.>

Lighting Question... actinic, reef... temp. lamps   10/14/08 I have read over many of your FAQ's but i still am not sure what to do. My tank is 48"Lx24"Wx22"D, currently I have a 48" Odyssea 2x 250W DE HQI 20K bulbs, 4x 65W CF Actinic Blue, 6x Bluemoon LED. It hangs approx. 9in above the water. I switched from 15k to 20k to highlight the corals more (polyps, purple tree gorgonian, finger leather, spaghetti finger leather and a carpet anemone. My problem is now i think it is too blue, should I switch out the 4 Actinic for 4 50/50 or 4 10k CF's? <I would, yes> I like the 20k's but I want to make sure there is enough light, I could switch back to the 15k. Jason <You could. Bob Fenner> Thanks Bob, I've been racking my brain since I switched them over. Jason Panek <Welcome Jas. You can see my comments posted on WWM re actinics... "whites" are better functionally by far... aesthetically? BobF>

Lighting, SW, sel.  - 7/23/07 I have a reef tank that is 49" across, 29" front to back and 24" deep. I have 3@400 watt, 20,000 K halides I run for 9 hours a day. I have 6@ T5 bulbs that are 48" long that run for 13 hours a day. I have sps, LPSs corals and 5 clams that are all doing great. I would like to give the best lighting possible to my corals for maximum health. If you could share with me the type of bulbs (brand, size , etc. .....),length of time they should be on and any other pertinent information on lighting that would make them as healthy as possible it would be greatly appreciated. I least understand what type (Actinic.6.5 daylight or ?) <Actinic not necessary...> of T5 bulbs to use. I have heard the Giesemann T5's are best but ? If this is true how many of each type would you use? Thanks Al <... this sort of information "comes and goes" with new makers/re-labelers, and time of course. We invariably refer folks to BB's for wide actual-user input for such gear issues. Please write to "the usual suspects" (wetwebfotos.com, reefs.org...) re. Bob Fenner>

UV Hazard, Real for Cnidarians? 7/13/03 Seems as though the consensus among you all is that MH lighting requires some sort of UV filter. <not always... depends on the coral you keep. Some need UV to keep their natural color... others change or suffer due to excess exposure. Health and vigor issues too. I lean towards allowing UV into the tank... but not into the room (protect your eyes via a closed canopy)> However, I have read elsewhere that MH lighting does not produce nearly as much UV-A, B or C as the sun and in that context, shallow living reef creatures can handle it. <varies by lamp> I've got 3 X 175W over a 175 gallon, 24" deep tank (not sure of the brand, box was unmarked as to manufacturer but they are 10,000K with mogul base). <do inquire about bulb brand.. some are just terrible, others like Ushio/Aqualines and Iwasakis are very good> Is this a matter of debate or would you say there is no question regarding UV hazard? Regards. <depends entirely on the species being kept and from where upon the reef it was collected. Most corals are adaptable over time at any rate. Best regards, Anthony>

LFS Opinions and Publication Truth 9/13/04 (MHs, light, corals) Good morning, guys! <cheers> Please push Ivan away from us here in South Louisiana and push it farther away from Florida! <heehee... if only I could> The last thing they need is more rain! I visited my LFS/LRS, probably the best one in South Louisiana, yesterday. I had intentions of purchasing a 6500ºK bulb for a pendant I have, and probably a 175w 10,000K setup for my 58g. They freaked out when I asked for the 6500. <bizarre... I cannot fathom why> Now, every book I've read, new and old, has suggested that lower Kelvin can be advantageous and economically friendly to some corals. <exactly... it is THE best light for a majority of corals> Information gleaned from wetwebmedia.com, the best source, IMHO, suggests the same. The owner, normally a helpful guy, tried to tag team me with a scientific sounding employee into discovering that 6500 is the way of the dinosaurs and I should learn from their mistakes and buy the 20,000K. <wow... not only are they mistaken, but 20kK is actually not helpful for a majority of corals... that is to say - used alone, 20k K will suffer many photosynthetic corals because they lack adequate amounts of daylight in the spectrum to stimulate adequate photosynthesis.> I asked how PAR ratings compare to the "plain-ol'" 6500s and how 20,000 is better, other than just marketing and personal preference. Grunts and mumbles followed. <do a google search for "Sanjay Yoshi" to read some of his studies and results regarding PAR values> The scientific guy said he wouldn't hesitate adding a 400w 20,000K to his nanoreef tank, again going in the face of anything I've read. What's the opinion from anyone over there? <they have caught up in the hype... there is no basis for using heavy blue/20k K only... quite the contrary for garden reef displays> I think Mr. Calfo would have something to say. I would really like the experienced, non-sales driven opinion here. Once again, thanks! Ian <with kind regards, Anthony>

SPS lighting Hello Mr Fenner, or whom ever answers :) <Steven Pro tonight.> I have had so many mixed opinions about the kind of lighting I need for my 75 gallon tank (48X18X22). I want to have SPS at the top of my rock work. I have this cliff made up and I thought it would be lovely to have a mixture of SPS there. They would be about 8-12" from the lighting. I want to have all verities of clams as well. I would also like to have at the dimmer and shady spots of the tank a few (frogspawn, bubble, open brains) LPS. I have heard that 2 175watt MH 10K & 2 X 110 VHO actinics will not give all varieties of SPS the light they need. I have heard that I would be better off with the 2 250watt MH 6,500k w/ PC 96 watt actinics or 2 x 110 watt VHO actinics. If I were to get the latter I fear burning the LPS. <I agree. A real concern.> I am more crazed with the SPS (addicted more like it) and they would be my main focus. As well as the clams. I guess (though it makes me sad) that I could do without the LPS if it would be the best for them. I guess I am asking is if for a clam and SPS dominated tank, the 175 watter would be to weak. My tank specs are; 75 gallon drilled, 20 gallon sump with an Euro-reef skimmer, a 20 refugium on 24/7. 5" DSB and 100lbs LR. Ammo, Nitrites 0, 5-10ppm of nitrates, pH 8.3-8.5, Ca 450, alk 11dkh (good old calcium reactor!!) temp. 79 degrees, I use only RO/DI water. The tank is 15 months old. I have two clown fish, three cleaner shrimp, snails and my DSB dit-kit (worms-o-plenty) and a pajama Cardinal. I hope this helps and you won't mind putting up with yet another lighting question. :) Gracie <It is my opinion that most people that need to opt for higher and higher wattage lamps are using lousy bulbs with a poor spectral distribution. I think the 175's with 10,000K Aqualine-Buschke lamps would be plenty. The best tank I have ever seen uses this setup. -Steven Pro>

Lighting SPS's Hey guy's, bet you've never heard this one before, but here it goes anyway. I am breaking down my 75G reef tank and moving it to my 135G fish only. Obviously, I have found a home for the fish). I currently illuminate the 75g reef w a 175W-10k MH horizontal pendant (Approx. 18" x 12") along with 2-40W actinic fluorescents and 4x55W PC 10k. I have recently discontinued using the pc's as I saw no additional benefit after a couple of months. My Acros & SPS's are growing very well, but with little coloration. the tank is 48" L so I suspected from the get-go that I was under illuminated for these corals. <You are correct, sir.> My question(s) is this: I have acquired 2 additional MH pendants (10K) and plan to use over the 6 ft. long 135G tank. I also have 4x30W fluorescents that I plan to use. In your opinion, will this be enough to color them up--if not, what would you recommend? Your comments are greatly appreciated. Fred Evans, Dallas, Texas <That should be sufficient lighting. I would strongly suggest using Aqualine-Buschke or Ushio lamps, either in 10,000K, versus whatever you are currently using. -Steven Pro>

Lighting SPS and Maxima Clams  All and extra info is appreciated. I have found out from numerous sources that 440watt VHO is not enough to support sps and maxima clams for my 75gal 21"deep tank. Is this true?  <borderline leaning toward true depending on the species of sps kept and the depth in the tank at which you keep them> If so I will invest in metal halides. Do you suggest 2 250watt bulbs or something different?  <way too much light unless you are keeping the most delicate/difficult and demanding shallow water species. If instead you are happy with hardier Montipora species and common Acroporas (brown, green, tan with some colored tips) then you will be safer and happier with 2-3 175 watt lamps (10K Ushio or AB recommended if not 3-150 watt 6500 k lamps). Your tank isn't deep enough to warrant 250 watt lamps for fear of bleaching any LPS and soft coral you may want to keep as well> Do I need to supplement with fluorescents or is the metal halides more than enough?  <more than enough blue in the MH lamps... add only for your aesthetics> Do I need to hang it from the ceiling or rest it on a canopy?  <better light from a horizontal mount in a canopy... pendants focus/waster light> All and extra info is appreciated. <best regards, my friend... Anthony Calfo>

Lighting Hi everyone, Bryan Here. <Good day sir! Hope you are having a pleasant holiday weekend.> Question about lighting for reef tanks. I have a 75 gallon that I am thinking about keeping some soft corals since I am a beginner in reef setup. Looking at about 260 total watts of lighting, still not complete because I am still researching and haven't decided exactly what I want to add. My question is this, I have been looking at the 48" JBJ Power Compacts. I have read somewhere though that VHO can give a more blue/fluorescent look and the corals really stand out. <IME, VHO actinics are superior to PC blue lighting. There are supposedly better PC actinics on the market now.> I personally like the blue look and was wondering if this is true (about VHO). And if so, can the power compacts give off a more blue with the right bulbs? <Yes, perhaps now with true PC actinics on the market.> Last question is, do you want/or is it healthy for the tank to have a more bluish feel/look with the corals. <It really depends on the corals. Deep water LPS corals do benefit from actinic lighting, but it can be of little benefit to shallow water corals. All things in moderation and you should be ok. No more than 50% of your lighting in actinic for deep water corals and closer to 25% maximum for shallow water species.> Thanks for all your help. <You are welcome. -Steven Pro>

Corals Under NO Fluorescents Hi to you guys there at www.WetWebMedia.com. I hope you all are well. Two months ago, I started my saltwater fish tank and I'm very interested in putting corals in, but I have 5 fluorescent tubes (2 Sylvania coral star blues, 3 normal daylight tubes) all are 36 watts measuring 180 watts of light over my 55 gallon tank. <Ok> I have been told I can put in mushrooms, zoanthids, Sinularia, Sarcophyton, Lobophytum and some other soft corals. Is this correct? <Yes> Some other websites say that you can also put in brains, candy, torch coral and tongue corals with my levels of light (somehow I don't believe this). <It will depend on exactly what you mean by these common names. Take brain corals for example. I house a Trachyphyllia under 160 watts of NO fluorescent in a 55, but I would not attempt a Favia or Favites (also referred to as brain corals). The Caulastrea (Candy Cane coral) and many of the Euphyllias (Torch, Hammer, and Frogspawn) would also be ok. Let me suggest you get a copy of Eric Borneman's "Aquarium Corals" as a reference. It is excellent.> So, guys could you please give me a few species of corals that would live under my lighting levels. I wish you every fish keeping success. Cheers, Brendan <Have a nice weekend! -Steven Pro>

Lighting Confusion I have a 125 Gallon reef with mostly LPS.  Its been up and running for 6 years.  I have decided its time to get some SPS.  I would like to up grade my lighting from  700 watts of VHO to MH.  I don't know how much MH to go with.  I' m going back and forth between 175 watt and 250 watt ballasts, and to add to the confusion do I get two or three ballast and bulbs.  The water depth is 18 inches to the top of the sand.  Which way would you suggest I go.   <unless the tank will only have sps and clams, go with the 175 watt lamps at one per 2 feet. 250 watts of light over many soft corals and mushrooms can harm them in time (photoinhibition). Many LPS corals will outright bleach. 10K Aqualines get my vote. Ushios are quite good here too. No actinics needed. Do read more here: http://www.wetwebmedia.com/marlgtganthony.htm best regards, Anthony>

Lighting/Stocking Question Hi Bob/Anthony/Steven, <cheers, my friend> I am setting up a new reef tank.  Need some advice on the lighting.  Firstly, tank specs: Tank size: 72" (l) x 24" (w) x 30" (h) Sandbed depth: 5-6" deep in most part of the tank, which gives an effective depth of 24" Corals intended: Mostly light loving sps e.g. Acroporas/Pocilloporas/Stylophoras.  Some light loving LPSs e.g. Favia/Favites.  And a few Trachyphyllia (which I intend to shield from direct exposure to MH with live rock structures) <all good... do resist too many LPS here though. Especially the lower light species> Light:  3 x 400W MH (2 Iwasakis 6500 + 1 Radium 20000 or 4 Ushio 10000, not decided yet) or 4 x 250W MH (2 Iwasaki 6500 + 2 Radium 20000) <Yowsa... 250 lamps at most here please. Even with sps. Tank is too shallow (under 30")> It seems like I am sitting on the border between 250W MH and 400W MH.  I have listed my considerations down below a list seeking your treasured opinions: <easy one here> 1.  Sps will be sited from top of the tank to near the sand bed.  I estimate greatest depth will be around 18-20".  Likely it will be the Pocilloporas at the deeper end.  With this in mind, is the 250W MH enough at the greater depth?   <yes... its all about water clarity. Weekly carbon and or daily ozone in a perfect world. Yellow water and 400 watt MH will not be as good as 175 watt MH is ozonized water at 18-24"!> I intend for them to retain their colorful appearance. 2.  400W MH will be 6" from water surface, <Jeez?!?! Making lava, bub? 250W MH will be 7" from water surface.   <OK... getting better> The different height is due to the bulk of the 400W lamp holder. My concern is the presence of a central brace of the tank.  It seems that a 3 x 400W configuration will mean a MH light have a sitting above a 1/2 inch glass which I believe reduces its efficiency.   <oh, ya!> What is your take on this?   <the 400 watt metal halide rage is a joke perpetuated by an industry of rank amateurs. Ha! Ahhh... I'm not shy about an opinion here. What you have are a lot of SPS keepers keeping (and yes growing very well) sps corals in shallow water under 400 and 1000 watt halides, and then finding another reason for the deaths and bleaching events for specimens after 1, 2 and 3 years when photoinhibition is a strong factor. You will be hard pressed to find an aquarist with 400+ watt MH over shallow water (less than 20") with 5+ year success. A lot of folks under 3 years preaching though.> Offsetting the "middle" 400W MH is not an option IMO as I like both ends of the tank to be equally illuminated. 3.  Yet all the hardcore sps/clam guys are campaigning for the 400W bulbs, (I seem myself moving a little more towards sps already, though not clams), are 400W bulbs an overkill in my tank? <yep... you need 30" plus to make this argument> 4.  I read that many of the colorful coralline algae do not do well (bleach) close to 400W bulbs, in the event that I do go for 400W, at what depth will I start seeing colored corallines? <agree in premise, vigor by species. No rule here> 5.  I intend to shield my Trachyphyllia from direct MH lights, if you think it cannot be done, then I will drop the idea of keeping Trachyphyllia geoffroyi.  It should be a major facture in lamp selection. <they will be fine on the sand bottom under 250 watt. Just acclimate slow (see my fly screen method in the archives under acclimating corals to new light) or in my coral prop book> 6.  The top of the live rock structure will be populated with bushy Acropora.  I understand with 250W MH, I can put them close to water surface (give couple of inches for water changes), but what about 400W MH, can they be kept that high (if placed immediately below the MH bulb)? <most can be acclimated to the brighter light. Some will not. All can be acclimated to "lower" light if fed well> 7.  I will be installing a 8 gallon dump bucket fed solely by my sump return pump.  Estimate dumping frequency is about one every 45 seconds.  Please advise how much more water movement do I need in such a tank, assuming somehow I managed to keep water movement well spaced and random. <for sps, aim for a 20X turnover with random turbulent and or surging flow. No wave-timers please...a  waste of money> 8.  Do you know of anybody willing to ship pink Goniastrea?   <nope... requires Extreme (!) high light that will kill most other corals> I really appreciate your opinion call on the above, especially the MH. Thanks in advance Edwin <save some money bud... definitely 250 watts. You won't be disappointed. Best regards, Anthony>

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

The Right Light For Beautiful Corals? 10/25/05 Hi, Guys <Hey there! Scott F. your guy tonight!> Love your site. A lot of good info. <Thanks! We're thrilled to bring it to you!> I have a question for you about lighting for my 90 gal reef tank. I currently have all SPS and Clams in my tank. "Oh" 2 LPS at the bottom. I'm currently running Hamilton 2- 250 watt 10k halides 2-110 VHO actinics. I have been buying a lot of frags on line. For some reason, the colors of the frags don't look the same as in the pics. Is this because I have 10,000 K bulbs? <It's certainly possible. If you look on many e-tailer's web sites, the corals are photographed under 20k bulbs, which definitely do effect the color of the corals. Some unscrupulous vendors may actually doctor colors with software. I would venture to say that this is not too common, though.> If it is it OK to go with 14k or 20k radium's. Will the corals be OK. <Sure, corals will be okay, but there are other factors involved in coral coloration and growth. Water quality, movement, etc. are all in play. There are many hobbyists who maintain beautiful coral-filled aquariums with 10,000k bulbs.> Also is it normal for the SPS to only come out at night? <Many corals put out polyps at night.> I do put bio plankton in in between actinics and moon lights. <A good time to feed your corals!> Thanks, Jay  <A pleasure! Regards, Scott F.> 

Small Marine Aquariums
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by Robert (Bob) Fenner
Small Marine Aquariums
ook 2: Fishes
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Small Marine Aquariums Book 3: Systems
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by Robert (Bob) Fenner
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