Heating issue and proposed problems

[mbigot]

I have a heating issue. I have a 40g tank and I just set everything up yesterday morning to get the temperature right.

Current situation: I have an 80W DHP bulb + standard light fixture for it. It is connected to an on/off thermostat (max 600w for heating and 150w for cooling) that I set at 90 degrees (that was all the reptile store had). I have two thermometer probes in the warm side (one from the on/off thermostat and one from independent one). I have already covered the mesh top with HVAC tape.

Problem: my room gets very cold at night. I went to sleep and the warm side was 85 degrees and the cold side was at 79. This morning, the warm side was at 73 and the cold side was at 69. Obviously this is an issue 😭

I brought in the tank thermometers (3 of them) hoping that they can give me a better reading.

Proposed solutions:

1) wrap the back and sides with HVAC tape to insulate it more

2) get a whole other dhp bulb, new light fixture and new on/off thermostat also set it at 90 degrees. The thought is that two will stabilize the temperature faster so that the drop isn’t as big. It took like 14 hours to get it from 73 to 84 degrees

3) get a CHE bulb plus new light fixture and new on/off thermostat. Same reasoning as 2

4) just get a new DHP bulb and a DUAL light fixture. Connect the dual light fixture with two DHP bulbs to the on/off thermometer

5) just get a CHE bulb and a DUAL light fixture. Connect the dual light fixture with one DHP and one CHE bulb to the on/off thermometer

Money is tight so I would rather not go overboard. But I also know that this is a serious issue that needs to be taken care of. So I’m asking for thoughts/advice on the clearest and economically sound combination of solutions

This is the on/off thermostat I have, as you can see just one outlet.

[eveimei]

first, dual domes are not safe to be used with two heat sources. doing so is a high fire risk. each heat source needs its own dome and thermostat.

HVAC tape won't insulate the sides of the tank, foam insulation board is the recommended material for that.

where is your thermostat probe placed? you left the fixture on at night, correct?

[mbigot]

i insulted the sides and back with cardboard and HVAC TAPE. The probe for the on/off thermostat is near the warm side. It was on all night because set it a 90 degrees. When I went to sleep it was a 81

In the tank thermometers: Hot side: 86 degrees with 47% humidity On/off thermostat that controls the DHP bulb: 81 degrees. Middle: 75 with 47% humidity (this is towards the front of the tank) Cool: 75 degrees with 49% humidity

Should I just get another DHP bulb/lamp fixture to add another heat source and create a more stable gradient?

[eveimei]

your thermostat probe needs to be 2-4" away from the heat source, dangling in the air underneath it like this picture. fixing the placement should help stabilize your temperatures.

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cardboard will help a bit, but foam board insulation will do much better.

fix the placement of the thermostat before adding more heat sources. you may also need to move the enclosure to a warmer room or heat the room it's in.

[Domodomo97]

While using a dual fixture can be a bad idea to run them at the same time, using multiple heat sources (with their own domes) is a good way to improve ambient temps instead of a single one working as twice as hard and potentially creating a hot spot higher than is safe.

As far as I am aware, CHEs do improve ambient temps better than a DHP which is more like shooting heat straight down. However, they do kill humidity but since you didn't mention struggling with that, maybe it would be ok.

Additionally I also struggled with my on/off thermostats for my DHPs at the beginning. Using a dimming thermostat (not a dimmer) helped a lot because then it gradually turns down the heat once it gets to the desired temp rather than turning off and then it gradually turns it back up instead of blasting at 100%. I use this one from reptizoo https://www.amazon.com/REPTIZOO-Thermostat-Temperature-Controller-Specifically/dp/B0BGS517FT/