I don't want to panic you but I had this happen when I used the wrong silicone on my tank once. All the little stars I had crawled out and many started to kick the bucket - that was my first sign something bad was happening. A few days later half my SPS followed suit. So, keep an eye on things... 
 
Did you build your own sump? What silicone was used? 
		
	
		
		
		
		
		
	
		
		
	
	
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