i just got a BP(which i formerly owned) from a friend and the tank is all wrong. Its in what appears to be a 40 gallon tank with a sliding lid, however the lid doesnt lock into place becuase its bent and the tank itself is cracked in many differnet places. As a result im looking to rehouse the snake. Its approximately 3 feet long and weighs almost 800g, is a 20gallon tank an appropriate size or should i get something bigger? Also i have a spare hide lying around that i would like to use in his enclosure but its got a lot of speckles of paint on it and im wondering if this would be harmful to the snake.

thanks