So, I've looked through every similar post, and can't seem to find good answers.

I have a baby who is still in quarantine. Meanwhile, I'm trying to get the levels in his permanent enclosure right. No matter what I do, I cannot get it warm enough. I'm still reading 79 on the warm side and 71 on the cool side. I feel like I've done everything possible to correct this, but nothing's working.

I'm working with a 35 gal tank. Its been covered on 3 sides and top with reflectix and foil tape, with only the lamp area left uncovered. I have a large UTH, hooked up to a thermostat, set at 95. I have a 100w ceramic bulb, connected to a separate thermostat (probe directly under bulb, on top of substrate), set at 89. I have a thermometer with a probe placed close to the back of the warm side, 2 inches above substrate, reading at 79. Another on the cool side, reading at 71. It's only gone up a couple of degrees the entire time I've been playing with it. What gives?

The only things I can think of are:
-Maybe the substrate is too thick
-Maybe the water dish (placed mostly under the lamp for humidity) is absorbing the heat
-Maybe I should put reflectix on the bottom, too? This tank has feet so there's a little airflow underfiberneath
-Maybe I need a second lamp, though I've rarely seen anyone do this

Pictures below. The light you're seeing is just florescent, for daylight. I have 3 hides, one over the UTH. The substrate I'm using is a mix of loose coconut fiber and cypress.

Help?