I think that your main problem with a tank that size will be monitoring the frogs' health during the first few weeks or months after you acquire them. The frogs are often sold as undernourished juveniles that need to be well-fed until they reach adulthood. Many people seem to experience difficulties keeping them alive for any length of time. It might be a good idea to partition off a small section of the tank so that you can observe them feeding okay and quickly identify any potential health problems that may arise.