Next to my lowes is a mattress store, that I need to walk past to get to any of the other stores in the shopping center. I noticed the mattress store was having a sale on waterbeds, and had a big sign up about heated waterbeds.

I made a quick pit stop in to see what they use to heat them. Waterbed heaters are just like under the tank reptile heaters only in giant size. They had one that was 2 foot by 3 foot and 400W digital model, so I grabbed it, thinking I could use it in the new 5x3x3 pond I was building and keep it heated without something in the water.

I built up the bottom of the pond, so it wasn't sitting near directly on the floor, since that area of the floor has no subflooring or carpet. I put down a 5x3 1/2 plywood base, and stuck the waterbed heater on top. I drilled a small hole for the wires to run out and ran the digital thermostat up and mounted it on top of the post.

Talking to the mattress store guy, average waterbeds are 150 to 200 gallons, so I knew I was pushing it a little. (5x3x3 is 350g) but setting the thermostat, and then testing it with a thermometer, it was only off by two degrees. The default setting for the heater was 95, so I'm guessing people keep water beds much hotter, which is why the temperature wasn't that far off.

There seems to be less cold spots than with a heater in the filter or a sump, since it covers such a wide area, however replacing it if it fails will be a major problem.

Good pick up. I have always thought about doing that if I ever get around to building a pond. As far as replacing if you have a failure you dont....you go with something else...good luck, hope it works out for you.

Good idea saint_felony! Hope it works out well for ya.

Cool idea!

The mattress store guy said those heaters usually outlive the mattresses. Only thing he's seen kill them is if they're run in the open.

He did think I was nuts though.