Ok, I bought a 29 gal established SW tank from a guy who was graduating college and moving out of state and just didn't want to try and preserve it while traveling so far. He told me it had been up and running for about 4 years and he had never had any major issues. I'm brand new to the hobby myself but I've done tons of research. I'm the kind of person who has to know all about something once I get interested...any ways I set the tank back up at my home and the nitrates were super high I'm talking 80ppm.. so I did a 75-80% water change and waited 24hrs at which time the lvls were down to 15ppm. I went to my lfs and purchased 2 clown fish. They took to the tank instantly. The second morning one was completely covered in a white film and had white spots all over its sides..its color had faded entirely. obviously something was wrong and the other one was showing signs of white spots. When I went back to my lfs to ask for their help I walked by the clownfish tank and ALL of his were in the same if not worse condition than mine. He told me it was brooklynella and gave me some paragaurd...but it was too late for my fish. this was 4 weeks ago. What is the best/easiest way to make sure its gone from the tank completely before I add a new fish??? I have 3-4 hermit crabs and 1 snail right now but other than that and 50lbs of LR and 20lbs of LS those are the only living things in my tank. Any and all advice is welcome!