What size enclosures do adult ball pythons need? I have tanks ranging from nearly 100 gal to 75, 20, 10 gal (though I know thats too small)?

odd

20 gallon longs work out well, up to a 50 gallon one especially if you plan to breed. Ball pythons do not like being in an oversized tank without something to hide under or inside of. They like to have a hide regardless of the size of their tank. I have semi-grown BPs that will hide underneath their repti-carpet if they choose not to use their regular half-log hides.