Acquarium for Spirostreptus sp.

Dear all,
this is my first thread here so I hope do it alright
At the moment I own 0.0.5 Spirostereptus sp. in a plastic tank of about 60*40*40h (cm) and as source of heat I use a heat cable of 25W placed under the lid to reach 20/21°C in a room where at the moment there are 18°C. The substrate is made of a mixture of oak wood (rotten at various degrees), rotten oak leaves and wood dirt (from a non-coniferous wood) for a total of 10cm.
I just moved in this city, so I don't really know what to expect as temperatures during the winter, but I feel some changes have to be done to keep the correct climate.
First change will be adding more substrate, so the volume of air to be heated will diminish.
Anyway I would like to place these individuals in a glass tank (being more isolant that plastic), add moss and overall make it more eye-appealing, while still being pratical for reproduction and to keep track of the health of the millipedes.
I have quite limited budget, so I was thinking to buy a second hand Acquarium and modify it for my aim, but I don't really know where to start.
I red on the website that an Acquarium can be used, with low ventilation (from the lid) and as source of heat the fluorescent tube lamps, but I fear that this kind of lamp would not be enough and might decrease the humidity level, even though the moss would benefit from it being all my house quite dark.
So could you give me more information on how to modify the Acquarium, or what should I look for in a second hand glass terrarium? What are the pros and the cons of doing this?
I would like to start as soon as possible, as I own these individuals from a very limited time and I believe they did not started to moult or reproduce yet, things that would make the move more difficult.
Thanks to everyone who will help me

Update: asking around people said that aquarium might not be adequate because of low ventilation, which may lead to an excess of carbon dioxide at the ground level. Is there something that can be done about this, without going to an expert and asking him to make extra holes? As far as I know asking to make holes in glass can be expensive, on the other hand making holes on the plastic lid would be very easy to be done by me, but it will lead to an excessive dissipation on heat. As stated before I will place moss, but I'm unsure if its photosynthesis will be enough to absorb the CO2, especially because a lack of light might lead to a production of O2.
I know I'm asking a lot of questions, but I don't want to spend money on stuff and soon understand that is not suited for these animals.
Thanks again.