Currently I am using a large plastic storage box which I bought from Homebase for the pricely sum of £10. You will be able to find boxes such as this cheaper elsewhere no doubt but I'm afraid I'm rather lazy when it comes to shopping around. Anyway it measures 54(l)x35(d)x17(h)cm and has a few holes burned in along the top so my pets don't suffocate. I find that the plastic stays a little warmer than my previous all glass tank though it is harder to view the occupants.

Whatever cage you buy it's best to ensure it's at least twice as long as your largest millipede. I find that plastic tubs do keep the humidity in better as well but there is nothing to stop you using a glass tank if you can construct a good lid for it. Another thing to remember is that when it comes to "cleaning time" you need to be very careful you are not throwing any millipedes out. I usually only change half of the soil at any one time. I keep the half I'm going to throw out for a few months to ensure I have rescued all of the millipedes from it.

Substrate

The best thing to do for a substrate is to grab a bag of organic compost and mix in some well rotted oak leaves (or oak bark chips if you can get them) to about a 50/50 mix. Make sure there's about 5" of substrate in the tank for the millipedes to burrow in. You will notice the level of substrate go down a little as the millipedes eat the leaves.

Other decor

Driftwood/cork bark - provides hiding places for the millipedes where you can view them during the day.

Fake/real plants (if you use real plants be sure they aren't a toxic species as the millipedes will no doubt nibble them, pothos vines are good for millipede tanks as they tolerate a wide variety of conditions)

I normally scatter some leaf litter across the top of the soil as the millipedes will often be seen bumbling around the cage at night in their search for food.

Other equipment

You may find that if you live in a cold area (like Falkirk apparently) you'll need to use a heat mat. This can be taped to the SIDE of the tank and plugged in though if you plan to do this a thermostat would also be a good buy as heatmats can overheat and melt plastic. I simply place my millipede tank near a heat source in the house though not so close that the tank will over-heat. At the moment the milipedes live directly under my boa constrictors viv where the temperature is a steady 22.5oC due to him having a ceramic heater.