According to this link (see also this link, this link and this link), the salicylate test would appear to work by forming monochloramine and then measuring it so would definitely be interfered by monochloramine. It also appears that the salicylate test is for total ammonia and that is what it says on the test kit.waterbear said:It depends on whether you are using a Nesslers reagent test (shades of yellow to brown and only works in fresh water since the mercury salts are precipitated by chlorides in the water) which tests total ammonia and ammonium ion (NH3 and NH4+)so it very possible will test monochloramine (not really sure since this is not normally an issue with testing aquaria) or a salicylate test (shades of yellow to green and works in fresh or salt) which only tests for ammonia itself (NH3) so it should not suffer any interference from monochloramine. The salicylate test is actually the preferred test to use because Nessler's reagent can give a false positive for ammonia in an aqauarium when it is actually in the form of an ammonium compound that is not toxic to fish (such as when 'ammonia killers' are added to the water.)chem geek said:. Does anyone know if the ammonia test will get interference (accidentally measure) monochloramine? I don't know how the ammonia test works.
Ammonia + Chlorine ---> Monochloramine + Water
Monochloramine + Salicylate ---> 5-aminosalicylate + Hydrogen Ion + Chloride Ion
5-aminosalicylate --- (nitroprusside aka nitroferricyanide catalyst) ---> Indosalicylate
When I called to ask whether the ppm or mg/L units were ammonia nitrogen, the guy on the phone didn't understand and kept saying it measures total ammonia and then said the ammonia molecule, but most test kits (including a link above) say they measure in units of ammonia-nitrogen (i.e. 14 g/mole). It's not a huge deal since ammonia is 17 g/mole so not that different.