AC is bad for frogs. Make sure the tank is nowhere near any vents for the AC. The shift in ambient air temp outside the enclosure can cause a draft as well as cool the glass causing a cold zone on the cool side of the tank. This also fights the heat being produced by your UTH and heat bulbs.

To help hold in heat take some Sarah Wrap and cover the front half of the screen top where your lights are not sitting. This will help hold heat within the enclosure. Also you can wrap a towel around the bottom of the tank to help the substrate to hold some heat as well. Its not a good idea to place the UTH on the bottom of the tank. Especially not the tank you have because I have the exact same tank and that UTH for a 10 to 20 gallon will get really hot and burn your frog. It is best placed on the side of the tank. I have mine on the right side of the tank just about 1 1/2 to 2 inches above the substrate. Do not place the UTH over any sort of background or it will melt it of cause a fire. Nothing should be around the UTH.

Be sure that the Sarah Wrap doesn't touch your heat lamp either. Those lamps you have don't have a dimmer switch which is a must for Pacman Frog. The bulbs can get too hot and are much to bright for a Pacman frog. If you buy a Fluker's 5.5" Clamp Lamp with Dimmer and the lamp stand that goes with it you can hover the lamp just above the screen top so it doesn't touch. Also the Daylight bulb isn't as efficient at heating as the Exo-Terra Sun Glo bulb that has a concentrated beam. This bulb allows you to produce more heat with less light so you don't have to dial the dimmer on the lamp up very high to adhesive proper temps. At night you'd be better off if you switch to a Exo-Terra Heat Glo bulb. Its an Infrared bulb and will produce higher temps plus like the moonlight bulb it will not affect their day/night cycle. Both bulbs should be no higher than 50 watts and no lower than 25 watts, but you will need 50 watt bulbs because you're having so much trouble.

Keep an eye on the humidity levels because the lights will burn off humidity within the enclosure plus AC removes moisture from the ambient room air causing a dryer climate in and outside the enclosure.

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