Ammonia Test - False Possitive?

[Dr. Bogger]

Ok, well heres something new...

I have a Mardel Ammonia Live Monitor in my breeding tank, and that says there is 0 ammonia in my tank (none at all),
But on my API Ammonia Liquid Test Kit, it says the ammonia is 4ppm, what the heck is going on?

Am I getting a false possitive? or a false negitive?

Any ideas?

*Edit*
I have put some Ammo-Lock from API into the tank, could that be causing a false-possitive?

 

[tmack]

The API test will measure total ammonia - even the ammonia that's tied up by the AmmoLock. My test mentions that in the API directions. That's why I ordered the Seachem ammonia test - it will let you test for both free (toxic) ammonia, and total ammonia.

Edit - I have no experience with the Mardel monitors, but it would be nice to hear from someone in here how accurate they are.

 

[Dr. Bogger]

Thanks for the reply!

Hmm... i'm guessing it only mesures the toxic ammonia, as the mardel monitor says 0, and my API test says 4.0ppm (this morning it say 8.0ppm, but i did a 90% water change in a emergency)