Neptune Systems Trident Marine Aquarium Water AnalyzerThe Trident is an automated testing system that regularly tests alkalinity, calcium, and magnesium in your saltwater aquarium and then communicates this information to your Apex so you can get alerts, and change your dosing. When combined with the DOS (available separately) it creates a fully automated system for the proper dosing of supplements, maintaining them at consistent levels. Automatically performs Calcium, Alkalinity, and Magnesium tests