Ok TTM is no problem i fairly new to reefing but i have fresh water as well, running 7 tanks currently with a handfull of 20 and 40B lying around. I moved them to a 40B and all seem fine except the brown tang. I dont know if he will make it.TTM is tank transfer method of ich eradication.. basically you can move fish through a series of small QT tanks every 36-72 hours - in theory if done correctly you time the ich stages and remove them from your fish without the need for medication... I on the other hand use this method with medication - therefore, not only am I increasing my chances to successfully rid ich, but it makes it easier to ensure the correct amount of meds and serves as a 100% water change.
the only downside is you need a lot of tanks, or be willing to clean one out thoroughly every other day, and lots of salt water, because you are doing a 100% water change with each move.
some say it's more stressful on the fish, others say its less. i assume your mileage may vary.. i am in the middle of this now (mostly because I have a lot of fish and am terrible at catching them. i have run a cowfsh, orange beaked file fish, sailfin tang, gem tang, and naso tang so far with no issues.