Seachem MultiTest: Ammonia 75 Tests (950)
This kit measures total (NH3 and NH4+) and free ammonia (NH3 only) down 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 much more important to keep an eye on the level of free ammonia in your system.
This kit is based on the same gas exchange technology that is used in the Ammonia Alert and thus is the only kit on the market that can read levels of free ammonia while using ammonia removal products such as Prime, Safe, AmGuard and any similar competing products.
The other kits (salicylate or Nessler based) determine the total ammonia by raising the pH of the test solution to 12 or greater. At this high pH all ammonia removal products will be rendered ineffective, leading to inaccurate readings.
Specifications
| Test Type | Total Ammonia (NH3 + NH4+), Free Ammonia (NH3 only) |
|---|---|
| Detection Range | 0.05 mg/L |
| Application | Marine and Freshwater Aquariums |
| Technology | Gas Exchange |
| Test Count | 75 Tests |
FAQ
Can this kit measure free ammonia when using ammonia removal products like Prime or Safe?
Yes, this kit can measure free ammonia while using ammonia removal products such as Prime, Safe, AmGuard, or similar products. It uses gas exchange technology, which allows accurate readings without interference from these products.
What is the difference between free ammonia and total ammonia?
Free ammonia (NH3) is the toxic form of ammonia and is harmful to fish and aquatic life. Total ammonia includes both free ammonia (NH3) and ionized ammonia (NH4+), which is non-toxic. Monitoring free ammonia is critical for maintaining a healthy aquarium environment.
Is this kit suitable for both marine and freshwater aquariums?
Yes, this kit is designed to work effectively in both marine and freshwater aquarium systems.

Sophie Knox –
I’ve used this kit for several months in my freshwater tank. It’s easy to use and gives very clear results. I can now monitor free ammonia levels even when using Prime regularly. The readings are accurate and the test strips don’t interfere with the water chemistry.
Alexandra Chapman –
This kit is a game-changer for my marine setup. I was worried about ammonia spikes when using AmGuard, but this test works perfectly with it. The sensitivity down to 0.05 mg/L helps catch small changes early. Very reliable and consistent.
Tracey Bailey –
The instructions are clear and the test process is straightforward. I noticed the results are more precise than other ammonia test kits I’ve tried. It’s a bit more expensive, but the accuracy justifies the cost for a well-maintained tank.
Jason Mackay –
I switched from a salicylate-based test to this one after reading reviews. The free ammonia readings are spot-on, even when using ammonia removers. No false positives or interference. Highly recommend for any serious aquarist.