Don't underestimate them, Yes they do work and its easy to find out if they work or not. They are a visual indicator and I have stated time and time again they are super for starting a tank in the cycle as it will go through allthe color changes as ammonia agoes up and levels off and then comes back down and yu never have to drag out a test kit until its back to rthe safe level, to verify. I have added a fraction of a drop of ammonia to a tank it it took less than 5 minutes for the indicator to pick up the ammonia and indicate a change. They work. Just wave it over a open bottle of ammonia it will change color rather quickly. Do a test yourself with freshwater and some ammonia.....HOw fast it picks it up is dependant on the position its in the tank at, and how gfood of circulation you have. I position my indicatos near a filter pickup strainer or such. Oh and they also make smaller versins like Barry Baracudam and Rose Red etc which are all cartoon caracitures, and they are somewhat smaller. If the size of the indicator itslef bothers yu , just trimn it down in size but do not cut into the centwer of it where the indicator pad is.Its nly thin plastic and is easy tocut. The cartoon character ones are cheaper by about 2 bucks and much easier to cut down and make smaller without looking indcator color references. I just slide mine down between sandbed and glass in area of pump pickup etc and they work just fine.
