You could add a surface skimming attachment to your skimmer or filter. 
 
Once you solve the surface film problem, I strongly suggest you cut back on the tanks lighting schedule or you may burn some coral. I added a sump to my set up last year and lost a few corals since the surface film was quickly removed, causing light intensity under the water to suddenly increase. 
		
	
		
		
		
		
		
	
		
		
	
	
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