"George Patterson" wrote in message news:U7iWg.1379
I'm currently using Hagen and have no complaints. I tested my tap water
and got 0 nitrites, so I have some confidence in the readings I'm getting
on the tank water. I also tested some bottled water as a cross-check.

Do you need to mix salt into tap-water to check the test? Or do ammonia
tests work for both Salt and Fresh Water?