Well, if it is glass, you can best be sure this thing weighs a ton, literally, without water
Everyone that said just rinse with water is just about right. Depending on how much coraline build up inside the tank, that should be easy to remove, with a "glass" scraper, but if it is acrylic, I would use vinegar, soak it, and it should wash off that easy. Also, you might want to consider placement of the tank, because once you fill it with water, it would become a permanent fixture wherever you put it, so consider the maintenance you need to do, i.e., water changes, filter cleanings, etc... I would imagine, if it used to be saltwater, that it has all the filtration, stand, and canopy. I want to echo what everyone said about you being so freekeen lucky! that is a nice setup. Believe you me, your fish would be very hapy in that tank! If you are going to add wheels to the stand, make sure the wheels can support the weight or you know what could happen. Wheels make it easier to move it a bit if you need to get to the backside to install a new background, etc.. Keep us posted on the progress. One more thing, if you want it to speed up the cycle, see if your local fish store would give you some of their filter sponge to add to your tank to speed up bacteria colonization. Good luck again
