Thanks for the feedback. I put the heater in because the newts are in a utility room which gets down to about 5 degrees in winter, and whilst I appreciate that the newts will tolerate cold temperatures I thought it would be a nicer temperature for them with the heater. It only takes the tank up to about 15 anyway, but it will be coming out very shortly as the room warms up. Sorry, I don't know the tank volume in litres, but it is 18x12x15". The reason I haven't used all the height is because the tank is not very long and it is difficult to have the wood jutting out of the water whilst being secure seeing as it would be at such as steep angle. I did wonder about using cork or other synthetic land areas, but I do not think this looks as good as the driftwood.