Please help - can't get temps correct in new 4x2x2

[bobarnes]

So I recently purchased a new, larger tank for my beardie and in the process did a lot of research and upgrading (substrate etc. based on the pet shop giving me a lot of incorrect info at the time of buying him).

The new set up is great, however I'm having a problem getting the temps correct.

My heat bulb is a 100watt basking lamp in a dome. I have my thermostat at floor level in the warm end, but not directly under the heat lamp. This is set at 32C (the highest temp on my thermostat).

My basking spot is showing as 42-43C (measured with a digital thermometer with a probe), and the floor level of the basking spot area is around 34C. This all seems correct as far as I know, however my cool end is reading 23.5C. As far as I know the cool end temps should be 24C at a minimum, but more like 25-26 optimum.

I've had a think and these are the options I can think of and the possible problems with each:
1. higher watt bulb. The issue with this is that I think either the basking spot would get too hot, and/or the thermostat would cut the lamp and there would be no difference in the cool end temp regardless
2. move the thermostat probe more to the cool end and turn it down (e.g. 29 in the middle or 25 at the cool end), again though, I think this would overheat the basking spot/warm end
3. fit a ceramic heat emitter. If I went down this route where the hell do I fit it? If I fit it in the cool end there won't be a cool end anymore surely? I know that my thermostat can support two heat sources, however there is only one probe and I don't know where I would put this or how that would work at all.

Please let me know if any of my ideas are okay or if I've completely missed something! Desperate to get this all set up perfectly. If there's any more info I can give please do let me know.

Thanks in advance

 

[bobarnes]

I forgot a possible 4th option - to take off/change the dome around the lamp so that the light is more diffused around the entire tank rather than concentrated in one area. Would this work at all?

 

[CooperDragon]

It sounds OK since you're hitting correct basking temperatures. That produces a nice gradient down to the cool side which is more important than the temp itself. This will likely shift as the seasons change and the ambient temperature changes too. As long as you're able to keep the basking area temps correct and you have a good gradient the cool side temp doesn't matter as much.