An 81 to 85 heat gradient is really pushing the upper levels of safe temps for these frogs. Cranwells Horned Frogs and Ornate Horned Frogs are not "tropical frogs" they come from the Chaco region of south America and Argentina.
For froglets of this species I prefer to keep temps around 80 to 82, for juveniles and adults daytime temps between about 70 to 82 are just fine and leave room for some fluctuation. Night time temps can go as low as 65.
While the region they are from may be quite warm, these frogs occupy a mirconiche within the habitat that is far cooler than the ambient temperatures.
Tropical species such as C. Cornuta however require consistently warm temps between 78 and 82 f. With night drops to around 74.

Temperatures over 85 degrees can cause considerable stress on your frog leading to illness or death. And if you are shooting for 85 with your heating systems, then a slight fluctuation of room temperature can easily increase the heat inside the enclosure well over 85.

Sent from my SM-G920T using Tapatalk