Are you "nuking" the tank to reuse? Like a total stripdown and clean? If you are, then here is a wonderful bit of information by SRC from a previous post. I keep it in a word document as a reference as it explains the "nuking" process very well, and step by step. I hope SRC doesn't mind that I relay the information to you, but I just think it is so very useful, and I've said like 3 times that it's not mine, it's hers. If she wants, I can add a footnote at the end, but I think I'll be ok.
To Nuke a tank:
STEP 1. Mix up a solution of 1 part clorox to 3 parts water (if you are making a gallon of solution mix 1 quart clorox to 3 quarts water).
STEP 2. Let this soak for several hours...make sure all of the tank is submerged (or atleast make sure it is filled to the rim...so none of the inside is left untreated..it's best to soak it if possible).
STEP 3. Rinse the tank until YOU cannot smell the clorox anymore.
STEP 4. Sit the tank outside for 24 hours and let the clorox evaporate.
STEP 5. Fill the tank with water and let it sit a few hours, then smell the water to make sure all evidence of clorox has been removed. If you still small clorox repeat STEPS 4 & 5 until the corox smell is no longer present.
I have also heard ratios anywhere from 1 part chlorox to between 19-24 parts water, but that's to use, in my experience, as a weak dip to remove parasites from plants or decorations, without causing harm, and it is only to be done for 2 minutes or so. You then rinse in heavily-dosed de-chlorinated water for placement back in the tank.
You have the two options here, so I hope this helps a little.