I have never really had a temp issue since in the winter it gets darn cold and the house usually stays aroud 68 degrees and in the summer the sun is so high up in the sky that the tank barely gets any. In the winter I actually run a fan to try and blow some of the hot air out of the canopy into the house. I really like the xenia but it will spread like wild fire if it gets lots of light and lots of nutrients. I have heard that if you have lots of light then you will want to add iodine to really get the xenia going. I have pretty mild lighting so mine really don't spread, and I don't add iodine either. Mine where given to me about a year and half ago at about a third of their current size and seem to be doing just fine.