melev

While was in Des Moines during September for MACNA 23, my tank sitter contacted me to let me know the anemone was up to no good and that one of my corals had turned white. I thought it was just a little frag that was too close to the BTA, but when he sent me a picture via MMS, I nearly lost my mind. The coral was actually three in one spot, and the little frag that I thought was the victim was completely fine. Here's some of the damage.



This birdsnest was previously stung, so this bleaching wasn't a big deal.


Two corals that were pulled out were probably 6" in diameter and had grown in nicely over a six month period. The One-Shot product is there for a sense of scale (photographed on the blue walk board).



I tried to determine what would have been the cause. The sitter told me the skimmer overflowed daily, so I thought about possible spawning events. Water parameters were stable, ORP & pH were graphing well and the water temperature never spiked.

Then I thought about the lighting, because prior to my trip I removed the middle 400w MH bulb to take some comparison measurements.




If you compare the middle numbers of both images above, you can see how the XM bulb was pretty much 30% more intense than the previous bulb that was seven months old. During my presentation on this topic at MACNA, I told the audience how important it was to know this numbers and to adjust the lighting period to a shorter duration so the corals can adjust to the increased intensity. Yet I'd forgotten to do just that before flying to MACNA.

The strange thing is that the corals in question that died weren't in the 'hot' zone, but were off to the side. If you look at the spot between 430 and 245 in the second picture, that's the corals that were hit. Everything else looked totally fine. My guess is that one coral couldn't take it and as its tissue sloughed off, it took out two neighboring corals like collateral damage. That's my best guess.

In disgust, I didn't take out the dead corals for a week to punish myself for the stupid mistake. My LFS owner offered to replace the corals in question, but I told him what I wanted was the six months of time I'd just lost... if he could do that, that would be great. Of course that's impossible. I ended up moving a couple of other corals that were growing on the sandbed for the past few months into that area to fill in the glaringly gaping hole in my reef. That eased my pain, a little.

Please remember that your corals can be affected by bulb changes, and adjust as necessary.