hey and wlecome to the little ocean...
yea, i dont blame you on the look of saltwater tanks vs freshwater.... saltwater tanks look so much cleaner.. (when things are workin right, which is most the time)
but, before you clean up and prepare the old tnak you might want to do a little research on REEF READY tanks, these tanks are designed for saltwater systems in that they have an overflow and drain and return system drilled into the tank...
saltwater tanks dont use or rather they dont need filters like freshwater tanks, but we the moer intermediate and more advanced users, anyways, prefer to use sumps on a saltwater tanks.. this will allow us to place the heater, and skimmer and other equipment below and out of sight of the display tank..
but, if you want to use the fresh water tank, that is ok too.. many people do it all the time...
first, you got to clean out the tank.. the best way is to use bleach water... 1 cup bleach for each gallon of water...
and rinse and scrub and do whatever it takes to clean.
If the tank has stuff stuck to it you can soak it longer
maybe over night???
and then rinse with fresh water. maybe even use declor, if you are afraid of any issues, but reallisticlly, a couple of rnses and it should be good to go.
good lcuk, and thanks for stoppin in.
keep us posted.
bill