yes it is i used ro water from safway for a long time while running my old bow front but i still had nurtrient problems (idk if it was because it wasnot deionized) so i felt it was neccesarry to buy a ro/di unit but for more then any other reason it saved me money buying water 
		
	
		
		
		
		
		
	
		
		
	
	
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