Re: What chemicals do I need to check for ammonia,
I don't know what the reagents are in those over-the-counter test kits, but you could probably buy bulk reagents from Fisher Scientific online. Those were the reagents we used when I worked in the lab, and we always got mass quanities in bulk. I'm not sure how to make reagents, I only know how to use them, but I'm pretty sure, that if you and your friend are both chem majors, you can ask a proff of yours to borrow their Standard Methods book (or find one in the library) and you will find out all sorts of neat tricks in the book. I know the Standard Methods book we had in the lab was thicker than Websters unabridged dictionary, and it told you the outcome of every reaction that occures in nature I think.
Or ask the supply room manager of the Chem Department if they might know. Or you could wait until you take quant, in which case you'll have to know how to test for differnt things, so you'll learn how to make reagents and what different reaction results mean.
I just find it cheaper and less mentally exhausting to buy the test kits. Either that, or bring a water sample to my good buddy that still works at the lab and let him play with it on his lunch break. Good luck.
~~Colesea