Getting a 20 Gallon tank for Roborovski Hamster. I have some Questions, 10 pts best answer?

You may need a top depending on how tall the tank is and how big your hamster is. A ten gallon tank would be the perfect size for the hamster, the twenty gallon tank may be to big for a robo hamster.Also the aspen bedding would be fine. It's not going to kill the hamster.