Should a Pump be Removed from a Garden Pond in Winter?
Q. My neighbour tells me that I ought to bring in my submersible pump for over winter. Is it really necessary, because it would be such a fiddle trying to thread the electrical cable back up the conduit pipe when it comes to put it back?
A. This is certainly the time for getting the pump out of the water to give it a good clean and check for wear (also check the cable). However with the milder winters and the very slim prospect that pools would be frozen solid along with their contents, it is unlikely that leaving a pump in a pool would do it any damage. On the contrary, if the pump is supplying water to a waterfall or biological filter the weather may remain mild enough to warrant having the pump running for quite some time yet.
If the water temperature does not drop below 7C ( 45F) you may be still feeding your fish, in which case the biological filter would still be performing a valuable function. At around 4C (39F) biological activity has ceased and the filter will be operating only in a mechanical capacity.
The water itself becomes less dense and rises and so the cooler water is on the surface. Before it was at the bottom of the pond. At this point it is wise to bring the pump to the surface, say marginal shelf level, so that the pump is just circulating the top few inches of pond water. The fish can then remain fairly undisturbed in the deeper warmer water below. It is best to keep the filter active for as long as possible since without fresh oxygenated water the aerobic bacteria that digest the organic matter in the filter begin to die.
If you do have to remove a cable from a pipe or conduit, attach a piece of a garden wire that is at least as long as the electrical cable to the plug end of the cable. Remove the plug and twist the wire and the electrical cable together and smooth the join with a piece of insulation tape wrapped round it. Then as you pull out the electrical cable, you draw in the garden wire. This is left insitu as a draw cable for when it is time to replace the pump.