I just saw this and figured I'd share it all with you. It's a short article describing different ways test kits detect ammonia and how they demonstrated known ammonia concentrations. I hadn't seen this article before but some of you might.
www.bulkreefsupply.com
Week 13: Ammonia, not as simple as you think: the ideal tank cycle | 52 Weeks of Reefing #BRS160
It's Week 13 of 52 Weeks of Reefing, and we're talking ammonia, bacteria, and the nitrogen cycle. We will explore the methods of using bacteria to convert this highly toxic ammonia into safer nitrite and nitrate as well as the final stage of nitrogen gas where it can leave the tank for good...

