Is this a troll, or is it serious?
I hate to be harsh, but it's another example of people getting expensive animals without doing any of their research first. I'll NEVER understand that. A good book costs 15 bucks. Internet care sheets are free. If you found BP.net, how did you avoid seeing any care sheets?
You want to keep these animals healthy, and watch them grow up safely? House them separately, and use appropriate equipment to do it.
Get a proper thermostat, line some bins with clamps up over a heat cord, indoor/outdoor thermometers with remote probes, etc.
The fact that these animals are often hardy enough to be piled into a tank by an ignorant owner doesn't meant this is the way they should be kept. Eventually, that situation will cause problems, it's only a matter of time.