I've been using this Milwaukee pH meter for a couple of years, still ticking. Be sure and get a bottle of calibrating fluid. I don't use storage fluid, just a couple of drops of nutes in the cap after each use:
	
	
		
			
				
			
			
				
				The Milwaukee Instruments compact pH pen tester is often used to help maintain pools and aquariums as well as improve results for growers and quality in a range of food and beverage uses.
				
					
						
							
						
					
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