API Ammonia Test Accuracy
- Thread starter nzafi
- Start date
Are you rinsing your cuvet with DI water? or tap? and if you are rinsing with tap water, and is it treated with chloramine. Chloramine would leave enough of a residue to skew the test. If any of the above, you could buy DI water from the grocery store
When I worked in the lab, we always rinsed 3 times with DI water before, and after each testing session. We also used glass for cuvets, that would be acid washed at the end of the day. Plastic is full of interstitial spaces that can easily hold residue.
If that kind of aseptic technique would be skipped, there would always be ammonia noise residue.
Also for each test, we would run a DI blank, and a 2ppm standard, only after those 2 checks agreed, the water to be tested.
By doing the blank first, then the standard, the spectrometer was able to adjust calibration.
I believe rinsing with DI water is the key.
When I worked in the lab, we always rinsed 3 times with DI water before, and after each testing session. We also used glass for cuvets, that would be acid washed at the end of the day. Plastic is full of interstitial spaces that can easily hold residue.
If that kind of aseptic technique would be skipped, there would always be ammonia noise residue.
Also for each test, we would run a DI blank, and a 2ppm standard, only after those 2 checks agreed, the water to be tested.
By doing the blank first, then the standard, the spectrometer was able to adjust calibration.
I believe rinsing with DI water is the key.
Yeah I was gonna add that too, age of the kit could be a factor; I also wonder are you testing right after water changes? Possibly the water in your tap has slight ammonia, which is possible...
IME, when my API Master kit shows any greenish hint, I know I got ammonia. Because when all is fine, it is solid yellow, no question, no mistaking it. It's yellow. That's my usual reading. Been like that over 6 years.
The turbidity / clarity may affect the reading. The lighting (need bright day light).
Using a reference test tube with water that cannot have any ammonia should help.
The turbidity / clarity may affect the reading. The lighting (need bright day light).
Using a reference test tube with water that cannot have any ammonia should help.
Just beware that if the tap water ammonia test is not yellow (perhaps because of the chloramines or other chemicals), I'd use a different water source for the test - bottled water, filtered water, RO water, DI water, etc.
