I've noticed many people having trouble determining whether they are evaluating tests for CYA correctly among other tests.
The Taylor Technologies website has a lot of information on proper techniques and a few demonstrations or pictures.
Here is a link to what you should see when you test for CYA. (Scroll down for pictures)
http://www.taylortechnologies.com/Chemi ... ntentID=44
Here is a link to seeing colors, such as when you test for TA.
http://www.taylortechnologies.com/Chemi ... ntentID=35
Here is a link which you will find another link "view demo" which will show you the FAS/DPD test method.
http://www.taylortechnologies.com/Chemi ... ntentID=11
There is a plethora of great information at their site. Hope you enjoy it and find it useful.