I've been using the API stuff since I saw this thread, Chad. it hasn't hurt any fish or plants. I've actually seen a little improvement. I use the instructed dose in my 50 along with Flourish Excel as directed. It has eliminated the hair, turned the majority of the BBA red and much more palatable to the snails and the tough matted green algae brought its stool and mike on stage to tell jokes about how it was "Bubba" to API in their fight... Didn't touch it. I ended up pulling plants and hand picking the stuff off.
This thread has been extremely informative and interesting... Thanks for sharing it all. Looking forward to more!