This kit measures total (NH3 and NH4+) and free ammonia (NH3 only) down to not up to 0.05 mg/L and is virtually interference free in marine and fresh water. Free ammonia is the toxic form of ammonia (vs. ionized Ammonia NH4+ which is non-toxic) and thus it is a lot more important to control the level of free ammonia in your system.
This kit is in keeping with the same gas exchange technology that may be used in the Ammonia Alert® and thus is the only kit available on the market that can read levels of free ammonia whilst the use of ammonia removal products such as Prime®, Protected™, AmGuard™ and any similar competing products. The other kits (salicylate or Nessler based) resolve the total ammonia by raising the pH of the test solution to 12 or greater. At this high pH all ammonia removal products will breakdown and rerelease the ammonia, thus giving you a false ammonia reading.
Fresh or saltwater use
Measures free and total ammonia