Only unseen solution I can think of is your calcium is elevated causing calcium carbonate precipitation thus lowering the alk. That being said if your corals are growing like weeds I doubt your levels are wonky. 
 
I have a feeling your deficiency is due to a whack load of coral, I was dosing near 150 ml of both solutions when my 120g was running. Might be time to choose yourself a fancy little reactor. 
		
	
		
		
		
		
			
		
		
		
		
	
		
		
	
	
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