75*F is Ok at night, but really they would prefer 80-85*F during the day. Being coldblooded it helps them with their metabolism, so that they can move around a little. It also is very important to have the temps over 78 at minimum before you try to feed it. Without the higher temperatures, they can't properly metabolize their food, and that can lead to health problems later on.

Also, if you haven't already installed the UTH, wait. Pacman Frogs instictively burrow when they get too warm. They burrow to cool themselves. It is important for Pacman Frogs to have the UTH mounted on the side of the tank. 1) because you don't want to mess with their insticts (they don't understand when it doesn't work like they want it) 2) Your Pacman Frog could burrow down, and if unprotected, could burrow right over the heater. Unfortunately, many Pacman Frogs are burned like this.

If you already have it mounted under the tank, don't try to remove it and put it on the side. UTH have very weak wiring that if broken could cause electrical issues and fry your tank. That isn't good. If you have a heater mounted under the tank right now, unplug it. You can try to find some kind of barrier to go over it at least 1/2" over the heater so your frog is less likely to get burned. That still isn't ideal, so I would be saving up for another heater while this method is in place. Also, make sure there is absolutely NO standing water at the bottom of the tank, even if there is substrate there, because if the hot glass gets wet, it will bend, crack, break up, and could fail.

Glad to hear you got some cocofiber. You have a very cute Pacman Frog.