id go slightly bigger, had a lot of the smallest ones and they were all rubbish at keeping a steady temp, the set ranges are too wide most were about 3 degrees each way so it would yoyo. Pretty sure one was the hydor.. ill check.
easerthegeezer said:will need a heater mate, dont think they would take kindly to freezing temps. Why not just have it in the house? you trying to hide it from the missus? lol