Hi guys!

I am a little desperate...
My BP was in a tub for the past few months and it has really been tough to keep temperatures/heat at a correct level. I have been fighting all winter to get a decent temperature and was completely crushed today when a visit to the vet's confirmed what I feared; respiratory infection. The vet told me to go back to a tank but the one I have is a bit small for my boy...

I would rather have him in a tub, for financial reasons, but I'm at a loss as to how to arrange it.

My BP is about a year and a half old, weighs 900g and is about 3 and a half feet long.

What I have right now:
-water dish
-a hide (flower pot with a hole in it... he can't fit in it anymore)
-UTH (believe it's a small one)
-Hygro/thermometer with probe
-newspaper for substrate
-heating lamp

I saw the setup explanation for the glass tank but would anyone explain how to arrange a tub properly??? Zombi and I would be eternally grateful. I am so worried

Also for those of us who have pretty intense winters (I'm from Montreal), how do you manage to keep temperatures and humidity levels ok during the stupidly cold season??

Thank you.