The only chlorine tester we have found are the test strips and we learned pretty quickly not to trust those. I kept getting zero readings after de-chlorinating the water so was pleased with myself about that. Then it occured to me to test the water right out of the tap and still got a zero reading.
A quick look around the municipality's website got me all kinds of info that our water is treated both with UV and with
chloramine. There are specific warnings that the water is unsuitable for aquarium use without being de-chlorinated. My only explanation for zero readings from the tap is that there must be a difference between testing for chlorine and for chloramine.
Now I just toss in some de-chlorinating solution and trust in it. So far so good. I'm consoled by the fact that overdosing with the de-chlorinator is unlikely.