10 gal for adult pacman.

[Dabrute]

eco earth and moss will keep the humidity up right?

[GrifTheGreat]

eco earth and moss will keep the humidity up right?

You don't want to use moss if you are planning on feeding the frog in the tank. If they eat some of the moss it may become impacted(severely constipated) which can lead to death.

Coco fiber and moss alone cannot produce the amount of humidity necessary for the frog's climate.
You will have to use a humidifier hooked up to your Hygrotherm. If you don't use a humidifier you will need to mist the tank periodically to achieve the necessary moisture level. Keeping the substrate moist will help and keep the frog from getting dry though.