First, read the article on replacing hoses
In the Head Mistress forum reference library. (And btw...if you're gonna replace the tank, replace all the hoses too). Rinse the entire system according to those directions. Before removing the discharge hoses from the tank, tip and shim it just enough to make whatever is left in the tank run "downhill" away from the discharge fitting. After removing the hoses, put plugs in the fittings before removing the tank.As the article says, have plenty of rags handy...and if there's any way to work a big trash bag around the tank before disconnecting hoses and lifting it out, it'll help to minimize drips from the leaks. After you've gotten the tank and all the hoses out, clean the area very throughly with detergent and water. Don't use bleach...it won't help. Then spray every surface with K.O. ...don't be frugal with it...don't rinse, let it dry for a day with the whole area open so that plenty of fresh air can circulate. Now the messy/stinky work is done, and you're working with all new clean materials in a clean odor-free environment. If you haven't bought the tank, I recommend Ronco Plastics. They were our prime vendor for more than 10 years because they make the best tanks--extra thick walls, more than 400 shapes and sizes to choose from--more than 100 non-rectangular--and you can spec the sizes and locations of your fittings, eliminating the need for "fitting relocation kits" and/or convoluted plumbing. You can find 'em online at http://www.ronco-plastics.com or you can call 'em for a catalog at 714-259-1385