TH heat tape questions

Setup - 55 gallon aquarium with foam board on 3 sides. top is setup with insulation ( foil and cloth like paper towels ) to help maintain heat and humidity. Tape is 6" wide 2 foot long. I have 2 thermometers in the setup on the hot side to double check my readings. I do have a hydrofarm thermometer ready to go to but have not hooked it up yet as I am still in setup phase and no animal is living in there yet. Substrate is coconut fiber at roughly an inch or less thick

Problem - both thermometers are giving me a reading of 89-90.7 with the heat tape at full power. Is this normal? I was under the assumption it would get a lot hotter. Is it because the glass is cooling it more? room temp is about 77 and the temp on cool side of tank is 80 with humidity at 60%

Heat tape is to create a hot spot, not heat the ambient temperature.
Have you placed one of your thermometer probes under the coco or between the THG and glass?

between the coco and glass is 96 right on top of the coco is the other probe and its 86

edit: temp is now staying at 98 under the substrate on top of the glass