Swapping the screen out for glass is easy. If you can repair a window screen in your house, you can do this. Just remove the cord holding the screen in, pull the screen off, clean everything up and then silicone the glass in. It's very easy. The problem will be if the frogs are in the tank, you will need to cover the tank until the lid is ready to go back on.
Education is the most powerful weapon we can use to change the world ~ Nelson Mandela