The aquarium heater does not give localised heating since the water heater
sets up convection currents which mixes the warm and cold water. The warm
water then heats the rest of the terrarium very effectively, especially as
the extra warmth tends to encourage evaporation and so raises the humidity
levels.
> Another idea - if there was a fishtank aerator blowing air through the
> water in the bottom of the tank, would that more effectively transmit
> heat from the water into the air? (especially if the air was being
> recirculated within the terrarium, rather than being drawn in from
> outside).
It depends what plants you are growing in your terrarium. I tried it for
Nepenthes but I found the aerated water splashed onto the pots and plants
and made them far too wet. If you are growing plants which appreciate a wet
environment then the aerator may be useful although I don't think you need
it to even out hot and cold spots.
> Any comments much appreciated!
>
> Andy
>
>
-- Phil Wilson (cp@pwilson.demon.co.uk)