Heat at night & humidity all the time

[Mein30]

Hello! I'm new to tortoise keeping and am struggling with head and humidity.

I have a redfoot tortoise, only 3-4 months old. He has a 4'×2'×2' enclosure with an acrylic pane covering about 75% of the top of the enclosure. The (ambient) temperature during the day stays at 85° F. There's UVB light that stretches across the entirety of the enclosure and he has a basking light. What I'm struggling with is keeping that temperature at night. I purchased a 100W ceramic heat emitter hooked up to a thermostat but even that doesn't seem to keep it above 75. His substrate is topsoil, coconut husks, and sphagnum moss. Currently there isn't a drainage layer, I am planning to incorporate that in next cleaning. In the meantime I mist the cage 1 - 3 times a day. Maybe my humidity measure is incorrect but it only stays around 60%. Any ideas on how to keep him warm and comfortable?

The picture of the enclosure was before I had the UVB and heat emitter, heat lamp is 1ft away from the substrate.

 

[wellington]

You want to first get rid of the moss. It's dangerous to the inside and limbs.
If you can't keep temps up with one ceramic heat emitter then use two. In the winter I always had to use at least two sometimes 3 depending on which enclosure it was
@ZEROPILOT can help better with what the temps should be.

 

[Mein30]

You want to first get rid of the moss. It's dangerous to the inside and limbs.
If you can't keep temps up with one ceramic heat emitter then use two. In the winter I always had to use at least two sometimes 3 depending on which enclosure it was
@ZEROPILOT can help better with what the temps should be.

What dangers are you referring to with the sphagnum moss? I've heard it's great for keeping humidity and is nontoxic

 

[ZEROPILOT]

What dangers are you referring to with the sphagnum moss? I've heard it's great for keeping humidity and is nontoxic

Those things moss does GREAT. And if I had geckos or dart frogs I'd use some.
The danger is that tortoises eat some. Either on purpose or by accident when it gets in the food. Moss can not be digested. And can cause deadly impaction internally.
What are you using for substrate? Top soil is not good for what we need here. Orchid bark works great. Simply pour a little water into the corners every few days to once a week.(whatever suites your enclosure) As the water evaporates it provides humidity. Nice high humidity.
Your daytime ambient temperature is 85?
That's good. And your night time temp of almost 80 is probably also good. As long as it gets back into the lower 80s and stays there for 100% of the day. And these numbers are very likely to improve once you've got the correct substrate media. So hold off on buying that 2nd CHE.
The photo is a bag of pure Orchid bark from home depot.

 

[wellington]

What Zeropilot said about the moss and it can also tangle around limbs.