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Last Login: 5/21/2008 7:51:17 AM
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Hi all,
I've been lurking here for a bit after being directed by a friend/fellow reefer for some quality knowledge. Nice place you guys have here. 
Anyway, I've noticed over the last week that my polyp extension on a few of my SPS has dropped to little to none, while others continue to thrive and grow like weeds. My early guess is light, but let's start with setup and you guys tell me from there.
Tank: 30g long, all-in-one
Skimmer: Tunze 9002
Light: 15000K 150 watt MH, 11hr photo period
Flow: Two modified MJ400's (~1000gph), alternating via AC Jr. once per hour
Temps: 78-79 at night, 79-80 during the day
Params: A/N/N = 0/0/<2mg/L, Ph 8.1 - 8.4, Ca 420+, 9dKH, SG = 1.026 always (topping morning & night, waiting on ATO), phosphate = ~0.2.
Maintenance: Weekly WC's -10g or 5g - and macro for nitrates. Light feeding of mysis and/or brine + DT's phyto once per day.
The tank is relatively new - about 3 months - but the parameters haven't budged since ending the cycle. I don't believe there's much I can do about the phos...I used marco dry rock and from what I'm told it may leech phosphate up to 8 months. If it's believed to be an issue, I can always run some phosban.
From what I read (over a year of research before setup - did my homework!), these parameters and my setup should be more than enough to sustain SPS successfully. However, they all came from a 400watt, multiple bulb environment and were generally housed closer to the surface. My single 150W is about 10" above the water, and the corals are 8-14" below the surface. Age of the bulbs is unknown.
First course of action: Install my backup ballast and light for 300W total and replace the bulbs with a pair of Phoenix.
Any other thoughts or questions? Please let me know, I would very much appreciate it.
Thank you,
Mike
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| Hi Mike, Welcome to the Marine Depot Forums. Can you provide some pictures of the tank? Is the tank only SPS's or are there others types of corals in there? What type of fish are in the tank? Are the corals that are affected only in one area or spread through out the tank? How are they in relations to the flow coming out of the powerheads?
________________________________________________ Keith "Simply put, you believe that things or people make you unhappy, but this is not accurate. You make yourself unhappy." Wayne Dyer
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Group: Forum Members
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Hi Keith,
Sorry for the delay. Between maintaining the tank in 98-deg heat, trying move the corals in the hopes to save them, a new puppy and building a car, things are a little crazy!
Ok, so to start, this is officially a lighting issue after the last two days. The corals bleached on the lighted side, while the opposite side had good extension - some were a total loss. More on that after, but I'll answer your questions first.
Here's a shot of the tank from a while ago (cycling) that shows the PH placement. The alternate once per hour, and the corals are all located along the vertical center or higher on the rocks for the greatest amount of flow and light. There's really no shortage of movement anywhere in the tank.
There's currently one rock with about 20 watermelon zoas, one hammer, one orange ricordea, and a crocea clam. I thought about chem warfare and ran some carbon - no effect. The only fish in the tank is one true perc.
So on to the lighting troubles...
All the frags came from a multiple-bulb, 400w environment placed no more than 10" under the water, with the lights about 12" above the water. My setup (listed above) is far less than that PAR-wise so my first thought was the weak lighting. I moved the corals all to the top of the rocks - no improvement after 12 hours.
I currently have a glass cover under the light held by the reflector to keep some of the radiation out of the tank for heat reasons. Well, apparently it is a far greater lighting limitation that I thought, because I removed it for two hours hoping to up the PAR slightly and ALL the corals bleached on the lit side!  Even my pink digi that was growing like a weed with great PE bleached. My crocea on the bottom of the tank is still happy as...well...a clam.
Now, I have no idea what to do - this doesn't make any sense. They came from a far more powerful (lighting) environment with nearly three times the wattage and bulbs with no glass protection, and yet my older 150W bulb killed them just by removing the glass. Is it possible there's UV protection in the glass panels and I unleashed a tremendous amount that the corals couldn't adapt to? This was originally a 72" dual MH/dual actinic system that was broken down to just one bulb for the 30g.
Any and all ideas are welcome. I was going to add the other ballast and bulb to try to match the LFS setup, but now I'm certainly wary.
Thanks for taking the time to read.
Mike
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Mike, are your bulbs single ended or double ended?
________________________________________________Keith "Simply put, you believe that things or people make you unhappy, but this is not accurate. You make yourself unhappy." Wayne Dyer
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| Double ended. Age is unknown. I have two new Hamilton 14000K 150W bulbs on the way, just in case. Although the new bulbs would bring the color spectrum back into the proper range if my old bulbs have shifted, I fear this would only up the intensity possibly making things worse...
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Single ended bulbs have a built-in glass sleeve that filters UV so there is no extra protection required. Double ended bulbs don't have this sleeve so they have to have a layer of glass between the bulb and the tank. It sounds like you removed this shield and turned the tank into a giant UV sterilizer.
I'm not convinced the original problem is at all related to the bleaching or that there really is even a problem. Daytime extension is mostly an artifact of captivity and does not relate to coral health. Only some of the factors that control polyp extension such as flow, lighting, and the presence of food are known. The animals extend their tentacles to feed and to regulate gas exchange and photosynthesis, plus probably several other reasons we don't understand. Not extending the tentacles may simply mean that all these needs are met, especially if there are potential polyp-eaters like shrimp or angelfish present.
It sounds like your parameters and lighting are sufficient. I would watch carefully to make sure nothing is picking at the corals, check to make sure they're receiving adequate flow, and look closely for predators like red bugs or Acro-eating flatworms on them. If all of those check out and the corals seem to be growing and in good health otherwise, I would just assume it's a nonissue.
Mike G.
Ha'ina 'ia mai ana ka puana.
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I was afraid of the glass issue. Looks like I found out the hard way.
I agree, and don't believe the bleaching has anything to due with the PE. The bleaching didn't occur until I removed the glass. There are no polyp eaters in the tank, so no threats should have been present. No red bugs or other parasites present that I can see.
Now that you mention the PE for feeding, photosynthesis, etc., I'd also read (on WWM, I believe) that if conditions are 'too perfect' (ample light, nutrient rich water, loads of flow) that there's no need for full extension of the polyps and that corals can actually brown. I'd also read that the wonderful colors produced by SPS are in reaction to UV rays, and the lack there of would also cause them to brown.
In either case, I doubt my relatively new tank and weak (covered) lighting created the perfect environment. From here I may still install my additional 150W and new bulbs, and try it one coral at a time down the road adjusting my photo period as needed. A couple fish and coraline production will be enough to keep me happily entertained while letting the tank further stabilize.
Again, if anyone has comments or suggestions, I value the opinions of this forum so please share.
Thanks,
Mike
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| I don't have anything extra to add except, take you time (be patient) and the tank will come around for you. Do you have a current picture of the tank? I would be interested to see the changes since set up.
________________________________________________ Keith "Simply put, you believe that things or people make you unhappy, but this is not accurate. You make yourself unhappy." Wayne Dyer
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I actually don't after removing the SPS, but I can grab one tonight and post.
I guess a quick update since removal - the tank actually seems much 'happier' now. I did a 10g water change, and even after still the skimmer is pulling some of the nastiest stuff yet. Perhaps it was all the dying tissue and slime from the SPS stress. Last night the water is the clearest I've seen it yet, and my orange ric and clam's mantle were enormous with great color.
I guess things are no worse for the wear, I just learned a hard lesson like so many other novice reefers do. Thanks for the advice and support!
Mike
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Now that you mention the PE for feeding, photosynthesis, etc., I'd also read (on WWM, I believe) that if conditions are 'too perfect' (ample light, nutrient rich water, loads of flow) that there's no need for full extension of the polyps and that corals can actually brown. I'd also read that the wonderful colors produced by SPS are in reaction to UV rays, and the lack there of would also cause them to brown.
Hmm, I'm not sure if this is what they actually wrote or if you misinterpreted something, but you're relating several factors that really aren't related. Polyp extension and water flow for all intents and purposes are unrelated to coloration. UV exposure also isn't really related to coloration. The production of colorful pigments and the position of the zooxanthellae in relation to the pigments is controlled by PAR, not UV. However, the two tend to covary so high PAR tends to come with high UV. There's really no benefit to increased UV exposure though, either with health or color, and ideally you would want high PAR with low UV. However, low PAR doesn't mean you will have brown corals. The relationship between pigment production, and zooxanthallae density/position isn't straightforwards and varies between and within species.
Nutrient rich water can certainly increase zooxanthellae density though and cause browning as a result.
Mike G.
Ha'ina 'ia mai ana ka puana.
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