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FAQs about Coral et al. Cnidarians System Lighting, Troubleshooting, Fixing

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 FennerLight/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, Lamps/Bulbs, Quality, Duration & Intensity, Night-Time, 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 Corals, Stony Coral Identification, Stony Coral Behavior,

Light alone can be a strong factor/determinant in your Cnidarian health and appearance, but current, many aspects of water quality and the presence of competing, antagonistic and predatory organisms must also be borne in mind.

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
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by Robert (Bob) Fenner

Dead Area in Reef/Lighting - 11/30/11
Dear Bob & Crew,
<Hello Joe, James with you today.>
Again, thank you so much for your passion and wisdom- you truly are amazing and have provided this wonderful tool for hobbyist around the world to use! Outstanding!
<Thanks for the kind words.>
You have helped me several times with my 54 gallon corner reef and through your guidance, the tank is looking great! The tank suffered a serious bout of allelopathy but has been re-stocked with much more appropriate and compatible species. Perfect diagnosis and solution!
Perhaps you can help with the last remaining issue. There appears to be a 'dead' area in the upper rear section of the tank (see graphic) where no species of coral seems to tolerate. Every coral that is placed there exhibits dramatic polyp retraction within 1-3 days. This has been an issue since the birth of the tank. My first guess was water flow, but this has been remedied and I'm almost positive that the problem is light related.
As you can see from the graphic, the area falls within the spread of the 14k HQI bulb (2 months old). I cannot determine if the area receives too much, too little, wrong quality, etc. of light. My local club has ordered a PAR meter that I will be able to borrow soon, but as of now, I'm confused. All other areas of the tank seem to be fine for coral growth. Most corals, in fact, seem to 'like' being placed under the T-5s and 'dislike' the HQI. A few seem to have little preference.
I have placed the following corals in this dead zone and have witnessed dramatic polyp retraction followed by a full recovery when placed under the T-5s: Candy Cane, Trumpet, Torch, Frogspawn, Galaxy.
The HQI is a Coralife, clamp-on unit with a Phoenix 14,000K bulb, positioned about 6-7inches from the acrylic lid. I have tried a 10,000K bulb with the same results.
Lastly, the lower half of the dead zone, does not seem to be a problem. The section consists of an elevated portion of rock, about 7 inches from the water's surface.
Any idea what the issue could be? I chose the HQI unit based on the odd shape of the tank along with the high quality of usable light that it produces. It's frustrating to see such an expensive unit do the opposite of what is desired!
I did not attach a photo but will do so if needed.
<One thing that comes to mind with HQI is UV radiation. Does the Coralife fixture have a glass lens covering the lamp?
If so, then the problem may lie with excessive lighting for the corals you have been losing. All but the Galaxy require medium intensity lighting. Another problem may be that most of your corals are Euphyllia, and they are one of the worst when it comes to allelopathy. There may be some stinging going on during the evening hours when sweeper tentacles generally extend.>
Thank you!!
<You're welcome. James (Salty Dog)>

Re Dead Area in Reef/Lighting 12/2/11
Thank you so much for your insightful reply.
<You're welcome.>
The Coralife HQI fixture has a glass UV shield around the bulb.
<OK, so no UV problem.>
I was considering raising the fixture by an inch or two. When viewing the area, it just doesn't seem to be particularly bright, the brightest appearing to be more towards the middle of the tank where the HQI and T-5 light overlap more.
<Bright, in this case, refers to the relative luminosity of the light, or how it looks to your eyes. This has to do with the way the human eye sees. Different spectrums appear "brighter" (more luminous) than others. Most of the PUR for photosynthetic inverts like coral is not in the spectral range that the human eye views as highly luminous or bright, meaning that the light appears dimmer to our eyes, even though it could be emitting more PUR for your coral than needed.>
Do you think that the corals are reacting simply to their closeness to the bulb?
<Possibly, try raising the fixture, experiment.>
I agree with your suggestions on medium light corals not being happy there but the Galaxy's unhappiness baffles me.
<That is why I brought up allelopathy, is very possible with Euphylliids present.>
There are no corals within almost a foot of this area (except at the very bottom). I would assume that these conditions would be about perfect for a Galaxy species. Again, this coral opened up again when placed lower in the tank.
<That should have told you something.>
I have a branching Montipora (Hodag's) frag that I was considering placing in this area as a test. Do you recommend doing this? In theory, this coral should do particularly well here but I honestly have my doubts based on past results.
<Again, experiment.>
Thanks for your time James!
<You're welcome. James (Salty Dog)>

To Cover Or Not To Cover; That Is The Question -- 12/16/10
Hello to all with the crew,
<<Hiya Beth>>
Haven't written in a while what with one thing and the other but I've a few questions.
Question 1: I have been running Power Compacts (2 10,000 K daylights and 2 Actinics along with blue LED's) on my 125 gallon (6 foot) reef tank for years with no issues however, the colors of corals I can keep seem to be limited to green or tan and random purples.
<<Hmm'¦ You don't give the wattage, but even if these are 96w PCs, I expect this tank could use a bit more, regardless of the stockings'¦and in the 10,000K range versus Actinics>>
Any other colors I get brown out. Reading multiple articles has led me to wonder if this is related to the high nutrient levels I maintain (deliberately as this is a lagoon type set up), which would contribute to a higher Zooxanthellae population per coral
<<One of several factors to consider>>
or to the fact that I have a double barrier between the lighting and the tank (moisture protecting plastic strip below lights and a glass canopy on tank to reduce evaporation).
<<Another contributor>>
Since both barriers can reduce UV lighting,
<<Indeed'¦along with total output across the entire spectrum>>
and corals color up as a protection against UV light,
<<A factor, yes'¦but in of itself, not the 'whole story' re coral coloration>>
would it make sense to remove one or both of those barriers?
<<In my opinion'¦yes. Removal of the 'plastic strip' will increase light penetration. Removal of the 'glass canopy' will increase light penetration and arguably, gas exchange>>
Do you think this would increase the colors on for example, my Acans or Favia? (both a rather bland grey or tan with color only at the oral disc)
<<Can only help in my opinion, considering the type and intensity of your current lighting system. But as eluded earlier, lighting is not the sole answer to coral coloration. As you mentioned, nutrient control can be a factor'¦along with nutrition/feeding and the availability (lack of) of key amino acids. Water chemistry is also a player here. An imbalance/shortage of bio-minerals can also cause some corals to lose color/intensity, in my experience>>
Question 2: I have an elegance coral who appears to be doing quite well but I have questions related to its feeding. I currently feed a little bit of whatever I am feeding the fish. This could be Formula 1, Formula 2, Plankton, Marine Cuisine, etc.., quite varied and something different every day but not much of it. I thought that this would be a bit more along the lines of how they eat in their natural environment but noticed in your posts frequent suggestions for larger, meatier feedings twice a week or so.
<<This is mainly if the coral 'is not' getting what it needs from your daily feedings. If the coral is feeding and doing well now, I see no need to change your methodology>>
Since I do maintain a high organic load (no skimming and very little true filtration, just random water movement), and since it does appear to be doing fine, should I just continue my current practice?
<<Sure'¦for the reason just stated>>
I do 30% water changes every 3 weeks or so and am not concerned with over feeding so much. The elegance, along with the Wellsophyllia, Acans, anemones, and Favia, appear to eat everything I give them and never regurgitate so I thought I was doing ok.
<<If this is the case then yes, I would agree>>
Other possible contributing factors:
PH: 8.3 ish (varies from 8.1 to 8.3
Nitrate: 10-20 ppm
<<Some Nitrate is important to both health AND coloration. These levels are likely fine for the biotope/livestock you have, though striving to keep it toward the lower end of this range may prove best>>
Alk: 9 to 11 dKH (I do have to buffer every week or so).
Calcium: 400 avg.
Phosphate: 0 but using API and have had other forums state a not very accurate test kit
<<Might I suggest a Salifert or Seachem kit then. Or if you want to get really accurate, one from Merck or Hach>>
Temp: 78
SG: 1.024
<<I would raise this to NSW levels (1.025/1.026)>>
Thanks as always for your advice and work.
<<Happy to share>>
<<Poor coral coloration is often a combination of factors in my experience. Try 'clearing the path' so to speak, for your lighting as discussed'¦and maybe lower those Nitrates just a bit (add a skimmer or some chemical filtration) and see what that does. Adding a couple more 10K PC bulbs would also help, in my opinion. You could also look in to some of the amino acid supplements available'¦and/or add some Selcon to your feeding regimen. Eric Russell>>

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)>
Re Lighting Causing My Coral Issues?/Reef Lighting 5/27/10 -5/31/10

Thank you for the quick response!
<You're welcome, and I'm sorry I'm so late getting back to you. Had a bout with intestinal flu.>
To answer your question I do 10
gallon weekly water changes. And to clarify....you think it's the spectrum of my bulbs and not the intensity of the light that is causing the loss of color to the corals.
<Improving the overall Kelvin temperature will be beneficial for better coral growth, and your corals are likely reacting to the higher light energy being delivered by the Ice Cap Ballasts. There are some good points to note in this link.
I am getting growth. But losing color. Besides changing out the bulbs is there any other issues I need to address?
<Yes, I would allow the magnesium level to fall to 1250-1300ppm and maintain there.
Secondly, when you change the lamps, lower the photo period by a couple of hours and gradually
increase by 15 minutes or so daily. Doing so should allow the corals to adjust to the higher light intensity.>
At some point I would like to lower the fixture so as to not have so much light spillover. But I don't want to fry my corals either.
<Not to worry, is rather difficult to duplicate the sun in light intensity.>
Comparing this tank to my last one I'm just surprised that a loss of 3 inches in tank height and the addition of Ice Cap ballasts to a 6 bulb T5 would cause me so have these many problems with the same corals.
<Oh yes, can happen. The Ice Cap ballasts overdrive the lamps considerably and create a higher intensity. This is the reason why we need to slowly adapt the corals/animals to the higher intensity light source.>
At least my fish don't seem to mind!
Thanks again for your input.
<You're welcome. James (Salty Dog)>

Lighting upgrade, Reef, Coral 10/22/09
Hi crew,
I have a 65g tank with a 20g overflow/refugium, 2 Clownfish, 1 Coral Beauty, 3 Green Chromis and 1 Lawnmower Blenny, and about 80+ lbs of live rock. I'm looking to upgrade my current 192w CF fixture so that I can start adding in a few SPS corals (only have a few LPS corals at the moment). If I take the 4w per gallon rule-of-thumb, it puts me in the 260-340w range (not sure if I calculate the sump in that equation).
<More wattage than this would be a good idea...>
I'm concerned with a new light heating the water up to the point that I can't control it anymore (use a small fan in the summer which drops it 4+ degrees, don't have or need a chiller now, and it would be hard/expensive to add one into my current setup), so I'd like to try and stick with a T5 HO unit. So, my questions:
1. Is there a calculation to estimate how much of a temperature increase I might expect from adding a metal halide bulb. Say, 150w per bulb?
<Mmm, not as far as I'm aware... we could try to configure one... based on the most plausible factors... Distance from water, air circulation, venting to the sides, top, turnover/vertical gyre rotation of water...>
Would it still be controllable with a small fan over the sump return as I do in the summer now?
<Should help greatly>
2. Is there much of a difference with the effect on water temperature between output on CF and T5 bulbs?
<Yes... T5 and T-lower are cooler>
3. An option for a T5HO only fixture tops out at around 234w. Is this a big enough jump from my 192w light to make a difference with my current (and future) corals?
<Placing the specimens closer to the surface interface is of more importance, but yes>
It doesn't get me in the 4w per gallon range which makes me wonder if its just wasted money.
<Better for you to study, buy or borrow a PAR meter, measure ambient useful photonic energy with your present set up, look into means of improving water clarity (e.g. RedOx measure, Ozone...)>
4. If 234w isn't a big enough jump, and I have to look at an HQI/T5HO combo, is there a cap for my size of system (heating of the water as mentioned previously and bleaching corals aside)?
<Mmm... temperature-wise? Likely a small wattage HQI (75, up to 150) mounted a foot or more above the water (will require you fashioning a canopy likely to accommodate the rest of the light fixturing for this size, shape volume. You'd do well to search re lighting, light on WWM>
Thanks for all that you guys do. You've saved me some expensive mistakes.
I've still made some expensive ones myself, but that's because I didn't go to the site first to do the research! I've been through the lighting sections, but haven't found the final answers to my questions (although I did find others I wasn't expecting!), but feel free to point me in the right direction.
Stouffville, Ontario
<Welcome. Bob Fenner, San Diego for now>

T5's without Individual reflectors..not enough? 01/19/09 Crew, <Jessy here> Quick question about my 75 gallon SPS reef. I'm trying to be as patient as I can be with this '¦but I'm getting frustrated! I have a 9 month old SPS reef with around 5 Acros and 4 Montiporas. I run a current Nova Extreme 8 bulb fixture'¦ 8 54 watt ATI bulbs without individual reflectors. My growth has been extremely disappointing! I see pictures on RC of Monti caps that grow an inch a month'¦ time have grown half inch in 5 months. Some of my sps are showing decent growth though..My birds nest sits on the bottom and grows about 3/8" per month(it's in low flow, most of my other corals are in high flow). My Acros are sitting high up, all are growing at a snails pace minus my red milli, it's grown about a ½ inch over the last 3 months. Colors are great and all parameters are in check(minus salinity that I address later) I'm considering upgrading to the new ATI sunpower. It's only 6 bulbs but has great individual reflectors. Will this be a lot more intense light than my 8 bulbs under 1 big reflector? Last question is about my salinity. I recently purchased a refractometer and calibrated it using the provided instructions. Last week it measured my salinity at 1.31!!!!! I've slowly been bringing it down and it's currently at 1.26-1.27. There's no telling how long my salinity has been this high..I've been using a hydrometer. Can high salinity slow growth? Thanks so much for your time and help! Seth <Seth, don't make the mistake of going out and buying more equipment to fix a problem with poor husbandry. Shedding more light on your corals will only lead to more problems with algae or worse, bleaching. 8 bulbs on a 75 gallon tank is PLENTY. I run only 8 54w bulbs on my 150g reef and have great growth on my SPS. To answer your question YES salinity is a HUGE problem for corals if it is as high as it was in your tank. That could be the singular problem right there. Since you didn't provide tank parameters I can't comment on what "all parameters are in check" means. But, you should also be testing for Phosphates in addition to Alk, Ca, and Mag. Get your salinity in order and make sure your tank is healthy and you'll see growth. Don't waste your money on new lights. Jessy>

Help with coral, ID, lambda.... 3/6/08 Hi Crew! Donna here needing help again. A local reefer gave me a frag of this coral about 4 months ago. She told me it was a Pink Birdsnest <... a Poritid? Mmm, no... Looks more like a Hydnophora species; a Merulinid...> and she had it under PC lighting so I thought it would be okay in my tank. A 20L with PC lights. I put it pretty close to the top. It was doing fine all this time and then I decided to change my lights. It was under 130W PC and I just got the Hagen Glo T5 HO 2X29W one actinic one daylight. I did this 4 days ago and now the coral looks like this. Am I correct in assuming the light is too strong? I moved it lower in the tank for now until I receive your response. Thank you in advance! Donna P.S. the pictures are reversed I couldn't figure out how to get them in the proper order...Sorry <Mmm, I would borrow (check with the stores about, or the local marine/reef club) a PAR meter... Too "guessing" to gauge how much useful light/change otherwise here. I would in the meanwhile use a bit of shading material as discussed here: http://wetwebmedia.com/acclimcoralslight.htm
Bob Fenner>

MH Tweaking 3/31/07 Hello there, <Hi from HI> I bother your crew way to <too> much so I will be short and to the point. <Sort of like me!> 125G display, all SPS, predominately Acros. Previously ran 3X400W radium 20Ks but my corals became very pale some bleached at the tops on an 8 hour photo period 14" from the surface. <Yikes... ever try placing your face this close to these lights?> I downgraded to 3X250W 20K Radiums, they run 9 hours @ 10" from the surface, and while the undersides and deeper Acros show more color, the higher placed corals are still very pale. <Mmm... have you heard of the term "photo-acclimation"?> I don't have a single coral in my tank I would consider "stunning" they were all "stunning" when I bought them, however they quickly grow very pale. <Can/could be a few "things" at play here...> I have tried adjusting the height however it takes so long to notice any change I feel fairly lost. <The lighting needs to "start" higher, screened, electronically dimmed... the animals lower... however less-intense initially... graded to brighter over a few weeks time...> My question is having ruled out all other factors like chemistry/flow/etc. and being fairly confident my problem is related to Photo period/distance from water, what suggestions would you give me as a place to start and how long would you give it to notice positive change? <Mmm, please read here: http://wetwebmedia.com/acclimcoralslight.htm and the linked files above> Is there something else I am missing in regards to this pale plague? <Mmm, could be... as stated, there are other possibilities... and you've presented no real data re actual measures, set-up, maintenance... Not a mind reader... but do have very strong intuition at times> Color aside the Milli's grow .5-.75"/month, the Montis grow like weeds, even the very thick branched Acros are growing at a very pleasing rate, they just look like crap. <Can you define this? Or send a pic? Not of the fecal material... Heeeee!> All frags show low/medium daytime extension and crazy full bloom moonlight extension. <Okay> Any guidelines or pointers would be great. The only other piece of info that's relevant is that I did start the new 250s at about 20" and brought them down 1" per week until they hit 10-11" <Oh! Well that's an equine of a different hue altogether... Perhaps there is some sort of allelopathy at play here... Again, you don't present a stocking list...> I don't know WWM crew, getting pretty frustrated. Thanks for your time, Jeff <Guess so. BobF>
Re: MH Tweaking, pale scleractinians... 4/1/07
SG: 1.026 PH 8.3ish dKH 10ish CA 400ish <Mmm... what is your Magnesium? Easy for this to get out of balance with Kalk use, some types of melted media in Calcium reactors> 20G water changes every Sunday I only keep a couple of fish (pair of black percs, pair of F. Pseudo's, Six Line. I have a peppermint shrimp, 2Xskunk cleaners, and a pistol. Flow is achieved with a Oceans Motions 4 way on a 4800GPH External Pump. I under skim slightly, using a 240G rated skimmer on about 300ish gallons I run a CA reactor and drip Kalk. CA reactor maintains about 10.2 dKH Kalk is only about 5G per week. but holds the PH and CA steady. I have undetectable Nitrate/trite/PO4 All water is with RO/DI with a TDS of 0 The 300g system is split 125G display, 80G sump, 75G fuge, and a little 25g AquaPod for a Mantis species only. <All this sounds/reads very well/as good...> All in all I feel like I have built a good system and I have good husbandry, I just have pale corals. I don't use any additives at all except about 1.5ml of P. Iodide daily <Mmm, I would add this only once a week... during water changes... This alone could be "the" problem here... I would not add Iodine/ide/ate more often than this unless you had good tests for, and a real need...> or at least when I remember to. I feed the corals reef chili about 2 or 3 times per week. I have a wide variety of Acro species (maybe 12 different) plus Pocillopora, Pavona, Montipora, all of which are pale in color. Bleachish tips, pale branches. <Mmmm...> I hope this provides the extra info you were looking for, thanks again for your time. <And lastly... am sure your water temperature is rather stable... Thank you for this further information, follow-up. I would expand your feeding menu here... including the addition of vitamins, HUFAs (like with the use of a product like Selcon). Bob Fenner>

Turbinaria peltata Dear Bob and Crew, <Keep waiting for one of our reef-types to chime in... hello!> I need assistance please. I have had a Turbinaria peltata in my 50 gallon tank since August of 04. I have noticed in the last couple of month some of the tissue starting to recede. Parameters are as follows: 50 Gallon Flat Back Hex Ammonia - 0, Nitrate - 0, Nitrite - 0, Phosphate - 0. Calcium 300/350 - Alk High on my Red Sea Test Kit <High?> Approximately 125 lb Texas Holey Rock almost completely covered with Coralline Algae. <... some of this rock is unsuitable for marine aquarium use> 1 - Yellow Tang approximately 3.5 inches long. 1 - Coral Beauty approximately 3.0 inches long. 1 - Lawnmower Blenny approximately 3.0 inches long. Assortment of Mushrooms and Button Polyps. I have a 300 gal/hr powerhead on lower right corner. I have a HOT Magnum 200 gal/hr in the middle upper right side. Emperor 400 on the left side just behind the T. peltata. I set a container of Kalk on top of this and drip it through the perforations in the top of this unit for make-up water. Could this be a problem? <Mmm, don't think so...> Lighting was 100 watts of 20K NO Light. I upgraded to Coralife 260 Watt Unit consisting of 130 watts of 10K and 130 watts of Actinics. This unit was purchased this past weekend. You can see from the picture that the coral is only 4" from the light source. <Yes> I target feed this coral with a combination of Mysis shrimp, Ocean Nutrition two to three times per week. It readily accepts what I feed it. I also dose 30 ml of DT's per week. This is mainly for my feather duster and gorgonian. Your thoughts please, I don't want to lose this coral. Thanks Dean <Likely the animal/colony is just adjusting to the new lighting... but am concerned re the "high" alkalinity... Put yourself in our place here... how high is high?... you don't want any more than 12-15 dKH... I would be checking the holey rock as a source of excess alkalinity... and either moving deeper light sensitive life when switching to more intense lighting, or partially shielding the lamps for a few weeks... when they're new or replaced. Bob Fenner>

Blinded by the light... (06/22/03) Hi, I have read facts and questions section and haven't find an answer to my problem. <Hi. Ananda here today, with an idea on this one...> I have a 34 gallon tank and was using 65 watt CSL Compact on it...I have Soft Coral which was doing fine. a week ago I upgraded to VHO Lighting, I now have 3-24" URI VHO ( 2- super actinic, 1-AquaSun)... <Oh my goodness... unless you *gradually* increase the lighting level over the corals, you can light-shock them. Imagine walking from a dark closet into the bright outdoors -- you tend to squint, don't you? Well, you have eyelids that can protect your eyes, but your corals do not have anything that can protect their bodies.> now the corals are not doing as good...two is dying...I went from 1.9 watt per gallon to 6.6 watts per gallon.... What's wrong...are the VHO Lighting too strong? <A sudden increase like that would cause problems, yes.> I wasn't home one time when the temperature went up to 87 degree in the tank... <Yikes! That undoubtedly compounded the problem. Not only too bright, but far too hot...> I am now buying a IceCap Fan.... <In the meantime, a small fan aimed across the top of the water will help.> What do u think is the problems the Light too strong or temperature of the water? <Both! The corals were not given time to adjust to the bright lighting, and that followed by the temperature spike stressed them further. I would put several layers of screening between the lights and the tank, until you get the lighting much closer to what it was with your CSL lighting. Then you can *gradually* remove layers of screening -- over the course of many days to allow them to acclimate to the extra light. Do look around on the WetWebMedia site and chat forums for more info about doing this.> would appreciate anything that can help thanks, Scott <You're welcome. --Ananda>

- Issues with Coral - Hi, I've had a 55 gallon reef tank set up for about 10 months with everything working great. However, recently (in the past 2 weeks), the corals seem to be slowly fading. Here's a list of what I have in the tank and its current health pulsing xenia--going limp over the past 4 days; fox coral--receding over the past 2 weeks; green bubble coral--seems to be fine; encrusting gorgonian--seems to be fine; Tubastrea--receding over the past 2 weeks <Is this fed on a regular basis with a meaty seafood?> frogspawn--isn't coming out as fully; candy cane coral--receding; all of the fish (Firefish, 3 Chromis, Clownfish, Flame Angel, Royal Gramma and Mandarin) are looking and behaving normally. I've checked the nitrates (5 ppm), calcium (400), pH (8.0), specific gravity (1.024), temperature (80). I can't seem to figure out what the problem is. I've got a Seaclone 150 skimmer, an under gravel filter, a penguin BioWheel 350 and 60 lbs of live rock. <First off, I would suggest removing the under gravel filter and substrate in favor of a deep live sand bed. I would remove any mechanical or bio filtration from the penguin since you have ample live rock. You may also want to upgrade your protein skimmer as it is a bit undersized (regardless of what they recommend on the box).> The light is a 260 watt JBJ (2 actinic bulbs and 2 daylight) which is on from 8 am to 10 pm with a 1/2 hour dawn dusk effect with just the actinic bulbs. The manufacturer doesn't recommend changing the bulbs until 14-16 months so I don't think that could be the problem either. <Regardless of what JBJ says, all fluorescent lamps should be changed at a maximum of every twelve months. 8-10 would be much better. Even though the intensity will have dropped and the spectrum shifted, I doubt it would be causing the problems you have described.> I'm planning on adding a 20 gallon refugium in the next week or so which I thought might help, but I was wondering if you have any ideas of what could be causing this problem. I can't think of anything else. Please help!! Thanks --Kirra <There was a similar problem with another aquarist who, after several full range water tests, discovered that the cord to his heater had disintegrated while submerged. Check all your wires, and do be careful. I would run a copper test to rule that out, then perform a large 50%+ water change. It is possible that a contaminate has gotten in there that does not effect the fish (like heavy metals). I would also pop in a poly-filter or two because they adsorb all sorts of nasties. Where is your top-off and water change water coming from? -Kevin>

Light Problem, Will the corals make it? 2/10/04 I just got a new light fixture today, a 4x65 CSL moon-lite. I had a 2x65 Coralife Aqualight. The new fixture came in with a dead 10,000K bulb, so on one side of my tank I have only the actinic bulb. Will this light be enough to keep my corals healthy for a week until the replacement bulb shows up, or do I need to run out right away and buy a daylight bulb? I have Xenia, Finger leather, star polyps, and Ricordea on that side of the tank. Thanks!-Ken <your best bet is to temporarily prop the canopy up so that the daylight bulb is centered over the tank. Actinic blue alone will not support your corals and they may suffer light shock if suddenly exposed to a new daylight bulb after a week without. Anthony>

Acclimating Corals To A Different Lighting Scheme Hi again ! <Hi there! Scott F. here today!> Lighting question. I have replaced 3x250 10k HQI bulbs with 3x250 20k HQI bulbs. <I use and love 20ks, myself!> I have SPS and LPS in the tank. (mostly SPS). What is your recommended acclimation schedule? I have heard dozens of methods. <I can't think of a better article on the topic than this little gem from our own Anthony Calfo. A great technique which every reef hobbyist should learn and use! here is the link: http://www.wetwebmedia.com/acclimcoralslight.htm Enjoy! Regards, Scott F>

Lighting Question 4 July 2004 Dear Bob and crew, <Hi Aloke, MacL here with you tonight.> I've been going through the exhaustive FAQs on the WetWeb website and these have proved very helpful to me. <Good to hear.> I have a question regarding lighting and corals turning brown. I use five 40 w fluorescent tubes on my 90 gal tank, three full spectrum (supposedly) and two actinic. Earlier, for two months I just used the normal day to day tubes, and none of my corals died but I didn't necessarily see any growth. <I know that there are brands of bulbs out there with 6,500 spectrums. Something that makes a difference is the depth of penetration of the light. How deep is your tank, where are the corals placed.> Most people nowadays prefer stronger MH lighting, or PC lighting.. which I can't afford now, at least for the next four to five months. I've heard of European tanks that run only under fluorescent lighting successfully, and I would like to know what you think of these fluorescent tubes. My tank houses soft corals mostly, as I know my lighting really is not suitable for most hard corals. <Very wise> so I'm going with mushrooms and zoanthids. I do have a clam though (which has done quite well) and an SPS (Porites, I think) frag. as well as a green moonstone coral. <I would think eventually they will need more lighting. But if they are doing well just continue to watch them. Honesty to keep the clams and SPS most people recommend 4 watt per gallon of water.> I noticed some of my polyps and mushrooms turned brown in my tank. While in the LFS' tanks, they were under really bad lighting. Often a big tank had only a single NO tube for lighting. Wouldn't the new, better lighting mean better colours on the corals? Someone told me this had something to do with symbiotic zooxanthellae - could you explain why this happens? <Animals from intensely lit areas of a reef that are not supplied with similar lighting in captivity may appear to change color as they shed unnecessary U.V.. reflective pigments. At that point, such animals may appear to be darkening in color, often to a darker brown or golden color. The aquarist often associates this with a decline in health, although that is not necessarily the case. The color change may be attributable to an increase in the population of zooxanthellae algae, or simply the greater visibility of resident zooxanthellae now visible in the absence of the U.V. reflective pigments. Whether the change is intolerable or not depends on if the coral's fundamental needs are being met by the decreased illumination. Many corals can survive in captivity with less surface irradiance than the optimum levels received in the wild environment so long as the compensation point of photosynthesis is met. We call this photo adaptation. And even without it, supplemental feeding of the animal can be compensatory. For more on this please look at this section of the WetWebMedia website, http://www.wetwebmedia.com/acclimcoralslight.htm> By the way - I live in Laos, a small country bordering Thailand, in south east Asia. <Wonderful and so nice to meet you.> My tank has two false Percula clownfish, two hermit crabs, about 20 pounds of LR (so far) and I don't intend on buying any more fish... if I'm really tempted I might get a royal Gramma, but that'll be it. I also have a 3 to 4 inch sand bed. The tank is just over a month old, earlier everything was housed in a 30 gallon tank. Thanks, Aloke <Good luck Aloke>

Shocking Corals Well, I bought a compact light for my 29 gal. reef tank today, and I think I almost shocked my corals. I have a 29 gallon reef, however, when I put the compact lights on everything kind of suck up and shriveled. I put the two strip lights, (1) 10,000K daylight and (1) 50/50 back on after about 10 minutes and everything that shrunk up was looking good again. The compacts had 50/50 lights and all the color seemed to disappear from my tank. I have relatively low light corals, mushrooms, leathers and yellow, green and brown polyps, watermelon mushrooms. What would I be better off using? Would the double strip light serve me better so I can put the kind of bulb they are used to in and take up less space? Thanks for any input. <The various wattages would have been helpful. I am guessing you currently have 2 20 watt normal output fluorescents and you exchanged them, temporarily, for a 55 watt compact fluorescent. The change from 40 watts NO to 55 watt PC would be fairly dramatic and needs to be done carefully. Everything you listed can and will adapt to brighter light (they may even grow better), but it needs to be done slowly. Shielding/shading some of the light or raising the PC fixtures up off of the tank somewhat is in order. We have discussed this procedure in changing from VHO or PC to MH's. Please look through the archives for a more in depth discussion. -Steven Pro>

Corals Wasting Away Hi: New here but was referred to this site by a friend. I have a DAS tank 56 gal. for about 4 years now. Everything seemed fine, a few coral died but that is normal I suppose. <Not really. There is some reason for it, perhaps unidentified but there is one.> I have tangs, angelfish, gobies, cleaner shrimp, etc everything seemed fine. I add RO water to top up, I have been changing about 1 gal each week approx. <Rather modest amounts> All of a sudden about 2 weeks ago, I noticed a big decline in coralline algae, the corals also seemed to close up. <Best guess, you reached a critical threshold with pH, alkalinity, calcium, allelopathy, etc. Something has built up or decreased overtime and now your corals are signaling a problem.> I run a 56 gal. DAS system, only add RO water to top up. Everything seemed to be going fine. My four year old elephant ear coral was a show piece. Now however its shrunk to a mushroom. My blue mushrooms have even shrunk more! I am completely baffled what is happening. My fish seem to be fine! I have VHO lighting and add calcium, strontium, and CoralVite since the beginning of my set up. I change about 1 gal of water per week, not always regularly. All my chem tests seem to be online......always online since I started the set up. <Without actual values I am severely hampered in helping you.> This is the first time I have run into a serious problem. I did have a Cyanobacteria problem at one time but cleared that up. I use the coral supplements very limited as this can cause a Cyanobacteria bloom. However getting back to what is happening now. I have changed 30 litres of water last night, and I am doing the same tonight. I hope tomorrow will bring some results. I have a lot of money invested in corals, the fish are fine. I run a Fluval filter, which I use Black Diamond carbon. I also have a Fluval filter just for bacterial correction. What should I do! <The water changes are a good idea. So was testing the water, but without the results, I cannot advise you further.> I hope this was enough info to give me some advise. <Not really> Hope you will respond. I had a friend called Tangster 1 on the salt water aquarium site, but he had been sick and unable to respond. Please let me know, OK? Will really appreciate some advise....I run VHO bulbs so lots of light........yours truly, Bev Parker <I would be glad you help you if you respond. -Steven Pro>

Light Shocked Corals? Greeting and salutations <Hi there! Scott F. with you today!> My problem is as follows setup: 300 Litres. Used to have 2 Actinic Fluorescents and 2 10000K White fluorescents -Recently changed the 10000k's to 2 x 150 MH and kept the Actinics . Power head driven protein skimmer which only does about 1 cup a week ??? Problem here ?? <Well, not a problem, per se- but try to adjust it to pull out a couple of cups a week, if possible> Fluval 404 Filter NO Calcium Reactor / doser My water parameters are good although monitoring my Calcium is a problem. I use reef life Calcium Supplements and Buffer tablets on a weekly basis. <Do try to monitor calcium additions closely...The calcium/alkalinity dynamic can get really out of whack if you don't test for these regularly> My problem is that about 2 months ago I purchased a small cluster of brown mushrooms and a tree coral . My tree coral was doing great all of his small little feelers where coming out and grabbing the water for food . Now 2 months later it hasn't opened up for about 2 weeks and my mushroom coral is dying . I do 10 % water changes every week , my lighting should be fine ...... Why is this happening to me ??????? Should I add iodine and all those other expensive supplements you find in the pet shops ???? Werner Schoeman <Well, Werner- it sounds like everything is in order here...However, it appears that the decline in the corals occurred about the same time you upgraded the lights. Mushroom corals, in particular, can be adversely affected by sudden changes in lighting (both intensity and spectrum). Anthony has a great article on this on the wetwebmedia.com site. Do check it out! I don't think that you need lots of supplements....just maybe a little patience, and some slight adjustments. Check all water parameters for any aberrations. then I think you'll see those corals come back! Good Luck! Regards, Scott F.> Werner Schoeman

Stressed coral - 2/12/03 Hi, <Cheers, bud> am curious if Mr. Calfo has ever seen anything such as the acropora in the link that I am sending. <Too often> I bought the lil bugger because I was stunned by the color on the internet and have received it today. Is this coral dyed? <Dude... if you thought it was suspicious or dyed, why did you buy it before asking about it? Seriously... I don't want to pick on you but it is a valid question. No surprise here... for the sheer amount of e-mail we get like this, it breaks my heart to see people that seem to forget these are live animals... not just commodities. Research every animals before you buy it and be confident that you understand its needs and can provide for them. Else you support a bad aspect of the industry> I noticed polyps down around the base of the Acro but don't see any on the branches yet but the branches are the bright blue. <to answer your question specifically, the coral is not dyed but it will likely be "died" soon. If it survives, I can assure you it will be a different color. What you are seeing is a coral that has been over-illuminated (likely by obscene wattage halides over shallow water). In turn, it expelled most of its zooxanthellae and the sweet colors you are seeing are simply UV reflecting proteins. Since they cannot translocate carbon as the zooxanthellae did to feed the coral, and since the aquarium does not have a supply of nanoplankton, this coral will likely die within 6-10 months. It might hang on a little longer. To try top save it (in wait for the return of zooxanthellae) you will need to have a source of dissolved organics (even lingering nitrates in the tank may help). European aquarists have promoted dosing of a nitrate solution (in Daniel Knop's book and my BOCP1) or dosing with ammonium chloride. In time with more appropriate lighting, the animal may return to a more autotrophic existence. Sorry to be a buzzkill, dude... but it is what it is> Polyps may be still hiding I guess but I have never seen this color acropora before. Any clues as to being dyed or not? What type of lighting should it be kept under and what type of water current? Please fill me in. Thanks, Jeff <I can't say about lighting without knowing the depth of your tank. No worries, check out the reef invertebrate lighting article in our archives... there is rates lamps and species groups and water depths. Best regards, Anthony>

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ook 2: Fishes
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