Review on Seachem Ammonia Alert 1 Year Monitor by Laboratories by Sandi Alexander

This is not designed to get the exact amount of ammonia into your aquarium. It is designed as a warning system. I use it to let me know when my tank has completed a cycle. It's not entirely accurate, but it was slowly changing, showing elevated levels of ammonia. I suspect some of the negative reviewers didn't read the instructions. It takes about 4 hours for changes in ammonia to be reflected. It was yellow for quite a while when I first put it in my tank, which I knew was high in ammonia. The packaging states that the initial placement in the aquarium will take a long time. If you need instant or accurate measurements, this isn't for you. If you have a new container and want hands-free approximate ammonia levels, this works great!