Agreed. Don't over worry. Keep up on your water changes and all your parameters will be fine. Any somewhat decent kit is fine. Even the cheap API test kits will show ammonia or nitrites. Is the level shown 100% accurate? Well, it really doesn't matter. Fact is the ammonia and nitrite level should be zero and it's not. It's an alert to you to find out what's going on. That's all that it needs to be IMO. As for your other elements, if you keep up on the water changes, you should be fine. Calcium might be important, but a ballpark is good enough IMO. It will tell you if you need to supplement calcium or not (which you should probably already know by the stock level of your tank).
Just making a point. Don't obsess over pinpoint accuracy. Keep up on your maintenance and just enjoy the hobby.
