Frequently Asked Questions
Help! My pond has iced up
Not always a problem
If the pond entered the winter in a generally health state, without an excessive build up of decaying leaves and debris on the base, and with moderate stocks of fish, there should be few problems.
The cold water will start off with a good amount of oxygen dissolved in it, and the fish, sluggish in the cold, will be using up less oxygen. Normally the fish and wildlife in the pond should be able to cope with the surface being sealed by ice for a few days without coming to any serious harm.
Pumps and filters
If you have a pump or filter still running, leave them on. The water movement will help to keep the pool water healthy for the fish. Avoid turning off filters and UV units unless you are forced to (e.g. if ice blocks waterfalls and causes water loss). If you have to turn them off, drain them down if they are exposed, otherwise water inside the units will freeze and could split the casings.
As long as the pump is below the level of the ice, it should come to no harm.
Prolonged cold
If you have no pump running, and the surface stays sealed for more than a few days, problems might arise. The oxygen levels may start to fall, and dissolved waste gases may start to build up in the water. This is especially a problem where the pond is heavily stocked; has a lot of debris on the base; or has snow lying on the ice, stopping light from reaching underwater plants. © www.aquapic.com
Keeping a hole open in the ice can reduce this problem. Don’t smash the ice, as the shock waves can upset fish. Melt a hole by pouring on boiling water from a kettle at least twice a day. Or better still, use one of the small floating pond-heating units to keep an area ice free.
If the pond smells stale after the ice has melted, carry out a partial water change using tap water conditioner if necessary.
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