Sherlock Holmes Investigates the Pond

With a bit of a thaw over the last few days, we began to wonder what was going on with our koi pond.  We could see only one soft spot in the ice from the pond heater where there should have been two.  Until this point, we suspected that the second pond heater was just covered under the thick layer of snow we had received, but when we could easily see one heater but not the other, I began to get suspicious.  I sent Sherlock Holmes, aka Ian, to investigate.

Detective Ian beginning his investigation.

The pond is deep enough not to freeze completely; it is about four feet at its deepest, which gives the fish room to swim around throughout the winter.  However, in order to help the koi fish make it through several months of subzero temperatures alive, we use two 100 watt pond heaters from November through to April to keep a section of the pond's surface from freezing over completely. This is to allow gas exchange;  otherwise, the CO2 from the fish and frogs' breathing and the breakdown of organic matter like old lillypads and autumn leaves creates something close to an anoxic environment where oxygen breathing creatures struggle to survive.

While some casualties are inevitable - last year we lost at least seven frogs and a few fish - I started to get worried when it looked like only one heater was working and I saw some dead fish floating around the hole.  Due to the size of the pond, two heaters are recommended, so it was time to figure out what going on.

Only one hole with some dead fish floating at the surface.

Detective Ian started by shoveling the snow off the surface of the pond and quickly figured out the problem.  Only one of the heaters was plugged in!  It looks like when the heater froze in the water, it managed to get pulled right out of the outlet and consequently stopped working.

Ian shoveling off the pond to see what was going on down there under all the snow.

A slushy mess of pond heaters and dead fish.

Unplugged?!

 This was a relatively easy fix.  While the cord wouldn't reach the outlet, we used an outdoor extension cord to make up the last few inches and voila! With everything plugged back in and a few more days of above zero temperatures, both heaters are back in prime working condition.  Sherlock Holmes solves another farm related mystery!