sick discus

Question
Hello, I'm writing to you in complete desperation. I have a 75 gallon fish tank containing 7 3 inch discus fish (different types of variety)After adding in a weather loach that had some  white "strands" growing out of him (girl friend gave it to me as a gift didn't know it was sick) All my fish have become extremely sick. My discus especially (most important fish to me) all seem to have this white thing on their eye thats growing on it. It starts off as this little bubble on their eye its white and just begins to grow and completly cover it. My temperature is usually at 84 but recently I've kept it at 86-88 because of the disease. My ph is at 6, my hardness 50ppm, alk 0 , ammonia/nitrite- 0. I use a RO filter with RO right and discus essentials and literally do everything they need so pleae anything you dig up will help.

Here are some pics: http://www.discusforums.com/forum/viewtopic.php?t=15994
(where I posted for help)

As you can see it starts off as this bubble but later proceeded to grow and swallow up the eye. And its spread to everyone in the tank. I keep up with my water changes, tried  medicine (Furan-2) which helped a little bit but then did nothing. I'm completly out of ideas and have already lost 1 elephant nose, 2 upside down cats, clown loaches, my pleco (he also had fin/tail rot when he died) And I just don't understand what its all from. Please help me,

thanks Daniel.

Answer
Daniel -
I'm sorry I pressed the wrong button when I was trying to respond to you. I am a bit overwhelmed right now with questions, but if you would please copy and paste and try asking either tina quiao, Ron Coleman, or Chris Robbins. All three are very good with diseases, and Coleman I believe is very good with Cichlids (Discus are a kind of Cichlid) and he may be able to help you better. I'm sorry I couldn't do more for you..