My SPS coral bleached!

[LoneStar45]

Im not sure what happened to my tank. last Saturday night everything was fine. Monday morning, I came in and both of my Frogspawns, my catspaw bubble coral have died and all the SPS corals near the top of the tank bleached out completely. The only thing I can think of was that my return pump glogged up a couple of days prior and I cleaned it up and put it back in. When I pulled the pump out of the sump, it stirred up some detritus and when I started the pump back up, it released some of that into the display but I certainly didnt think that would kill my corals before it filtered back out. Any ideas on what caused it and what makes them bleach?

 

[Travis L. Stevens]

What are your water parameters? How much light? How old are the bulbs? What type of lighting? How much flow in your tank? What's the temperature? What's your Specific Gravity? How are you measuring your Specific Gravity?

 

[LoneStar45]

All the parameters look good. The nitrates were up a bit probably due to the sump debris being sucked ito the tank. I did a water change that day and it looks back to noraml now. I keep the slinity at .025-.026. The bulbs are about 6-8 months old and I replaced one shortly before this happened. I matched the kelvin rating (15000) and the wattage(250) but it gave out a different light. It wasnt giving me the ripple effect that the other two do but I find it hard to think that could be the problem. I leave them on for about 10hrs a day.

 

[LoneStar45]

I dont think I have measured the true specific gravity but I use a hyrometer to get the proper salinity.

 

[RichConley]

I really doubt its the detritus being stirred up. Did you clean the pump with anything other than vinegar?

Any idea what the temp was during the time you were gone? Heat kills quickly.

 

[hahnmeister]

Top reasons why I have had corals bleach...
1. low alkalinity
2. light shock (too much w/o adaptation)
3. touched by another coral
4. temps are too high

Ill bet you its one of those. nitrates, phosphates, etc...will cause corals to stop growing...but rarely bleach it seems to me.

 

[LoneStar45]

I think its high temperatures. When my return pump clogged up, the chiller couldnt work becuase the water level sunk below the skimmers and there was no cool returning water. Just the lights and no return water for who knows how long.

 

[hahnmeister]

Thats very likely. Can you list some other corals you have? I can compare and tell you if that is the case because I have had a couple temperature emergencies in the past and know which corals tend to die from it first, and how. I remember LPS being the most sensitive, so that makes sense. But SPS were more determined by species rather than placement. I would have pink birdsnest, poscillipora, and a green cap die (and they would just bleach all over at once except for the tips), and they would be anywhere in the tank, not just the top. At the same time, none of my millipora corals showed any signs of overheating.