John
I used the old fish tank heater to keep my pond water warm.
I stuffed it in a ceramic type log thing for fish tanks.

Make sure you secure it somehow...if it breaks and you stick your hand in the water you'll get a new hair style or worse...not to mention your awesome new captives.

My Cumingi would really thrash around in their pond, this is why I mention it...I'm sure your already on it though.

Mike
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Mike's Monitors!