If you live in a country that has freezing winters that chill running water and form ice everywhere, then you may be wondering whether or not it’s a good idea to turn off your filtration, or to leave it running.
In this guide, we will explain the pros and cons of leaving your pond filter running in winter and help you decide what to do when snow and ice arrive.
Should I turn off my pond pump in winter?
Whether or not you should turn off your filtration during winter will vary from pond to pond.
There are many factors that can influence this decision, such as the type of filtration, climate, depth of pond and so on.
For instance, you may live in an area that gets so cold, running water freezes. If this happens in an external canister filter, the pipes can expand and burst, so it may be best to leave them off over winter.
However, there are ways around it, such as selecting different filtration or insulating the pipes and canister unit, which can allow you to still run filtration during winter.
Factors can push the decision but in the end, whether you should turn off your filter during winter is really up to you, as there are additional measures you can take which can allow you to choose either or, no matter your location and situation.
Should you leave a pond pump on all the time?
Your pond filter is essentially a life support system for your fish; without it, in a small space, the waste your fish produce will create too much ammonia and make the water turn toxic.
Your pond will also receive less oxygen and will have no water movement, becoming stagnant and creating an environment that is inhospitable for goldfish and koi carp.
However, there are times where the filter can be turned off, such as in winter, when all the processes in the pond slow down, the fish don’t eat and so dont produce waste and oxygen is much more easily absorbed in cold water.
But for the rest of the year, when things are running normally and the fish are producing waste, we highly recommend leaving the filter on at all times as it keeps the water conditions clean and stable.
The main reasons for running a pond pump during winter
Keeping your pond filter running is beneficial for many reasons as it further ensures the safety of your fish by maintaining sound water quality during winter.
While we did mention that fish don’t produce much waste at all during winter, there may still be things like dead leaves in the pond which can rot over time, producing ammonia and making the water turn acidic.
This is why we suggest removing dead leaves in autumn, especially if you plan to turn off your filter.
However, if you leave your filter running, then this is not as much of a threat.
Another reason for keeping your pond running is to keep the surface of the pond moving, preventing it from fully freezing over and allowing oxygen to diffuse.
Pros of keeping your pond pump running over winter
There are a few benefits to keeping your pond filter running that you should first know, before deciding if you should turn it off, as they could sway your opinion.
Here are some of the pros involved in keeping a filter running over winter:
- Keeps water quality stable and sound
- Filters out debris keeping the water clear
- Keeps oxygen flowing and water moving
- Prevents ice sheets from completely covering the pond
- Keeps nutrients moving which keeps plants healthy
- Constant flow of nutrients keeps beneficial bacteria colonies going
- Movement of water prevents fungus from growing and disease from developing
- Movement keeps minerals flowing maintaining a healthy pH and hardness
In short, keeping the filter running provides extra support and stability for your pond throughout the year.
Unless you live in a place like Canada where temperatures drop dramatically and running water freezes often in winter, then we would suggest leaving your filter to run, as it still provides many benefits, especially if you have a small pond.
Cons of keeping your pond pump running over winter
There are also several cons to keeping your pond running all winter, some of them can cause setbacks and create problems which may end up costing you money in repairs and fixtures.
These cons are more relating to the integrity of the filter, which is put at risk in extremely cold places:
- Ice can form in the filter and damage the impeller
- Ice can form in the pipes and expand, causing the pipes to burst
- Cracks in the filter or pipework caused by ice can create leaks and drain the pond
- The moving water spreads the cold to the bottom of the pond, removing a temperature gradient, chilling the pond
- Costs electricity to run
Scenarios where you don’t need to run a pond pump
While we always recommend a filter if possible as it will improve the welfare of your fish, one isn’t always needed, such as in winter when the pond freezes up and the fish are dormant.
As long as there’s a gap in the ice sheet to allow oxygen to flow, a filter isn’t necessary for these cold months.
If you live in an area where running water often freezes and you have an external canister filter, then we actually will often suggest turning off your filter over winter, so that the pipes do not expand and become damaged with ice.
Another instance where a pump may not be needed is if the pond is large enough to sustain fish naturally. If you have a colossal pond that is thousands of gallons with trees and bushes growing around it, you may not even need a filter as the pond’s size will be able to naturally sustain the fish.
We would recommend stocking lightly for ponds like this though, as even a 20,000 gallon pond can be overloaded if too many goldfish or koi are added.
- In short, unless you have very harsh winters, where running water in your pipes freezes, there is no reason why you should need to turn off your pond filtration system in winter.
You can turn it off if you want to save some electricity for a few weeks, but it is not a necessity to power down your filtration if you live in an area that receives only mild winters.