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What To Do If Your Pond Freezes Over

Winter is a great time of the year; but what does it mean for your pond?

08 December 2020

how to keep a pond from freezing without electricityWinter is an exciting time of the year. Snow, hot chocolate, Christmas music, family and friends all contribute to a wonderful time of the year. But what does winter mean for your pond? Will your pond freeze over? We have you covered, so don’t worry.

When your pond freezes over, the ice on the surface forms what is defined as an ice cap. This will spread to cover the surface of the pond and, in most circumstances, it will still allow gasses to be exchanged. So, the pond will still absorb Oxygen from the air and Ammonia will be released; this process will just be slowed down. Assuming your pond is in a healthy state before it freezes over, everything should be ok.

If your pond is ornamental with no fish you can relax, stay indoors with your hot drink as you don’t have to do anything to your pond unless you feel the need to do so.

Cold water usually has a good amount of oxygen dissolved in it, and any fish and wildlife will be using up less oxygen. If this is the case, aquatic life should be able to cope with the surface being ice capped for a few days. However, if the surface stays completely sealed for more than a few days, you will need to act.

What happens when your pond freezes over?

The oxygen levels may start to fall, and dissolved waste gases may start to build up in the water. Overtime, this could be a deadly combination and will prove to be fatal to your aquatic life. This is especially a problem with a heavily stocked pond; where there is a lot of debris in the pond; or has snow lying on the ice, stopping light from reaching underwater plants.

First Step – Remove Snow

If there is snow lying on top of the ice try to use a standard brush to remove the snow, as noisy methods can disrupt the hibernating fish.  This will allow light to reach your aquatic plants, enabling them to oxygenate your pond. 

Second Step – Make a hole in the ice

Keeping a hole open in the ice is a good idea to enable the gas exchange of Oxygen and Ammonia. As quietly as possible to avoid disturbing your fish, try melting a hole in the ice by placing a pan with boiling water onto the ice; this helps to melt it slowly without affecting the fish.

Some people advise pouring boiling water from a kettle at least twice a day. This is a good trick, but sometimes this can heat the temperature of the pond up and confuse your fish. So it is best to avoid pouring too much boiling water onto the ice.

Never, ever use a hammer and chisel to break a hole into the ice. If your water has frozen over, any damage caused to the ice will send shockwaves throughout the body of water due to the pressure underneath the ice. This can stress your fish out and potentially kill them.

Winterizing Ponds and Water Features - Garden FundamentalsHow to prevent your pond from freezing over

There are several methods which can prevent a pond from freezing over.

  1. Keep your Pump running – This forces the water to circulate and prevents it from freezing over. But try to keep the pump away from fish and below the ice levels of your pond. You do not need to filter your water as waste is at a minimum during winter.
  2. Keep an aerator turned on – Having an aerator running throughout winter will achieve the same as your pump; the air displaces water and forces it to move, preventing the surface from icing over. We actually recommend an aerator as one of our 5 Tips Which Can Make A Big Difference To Your Pond. On the benefits of aeration, please see our blog posts.
  3. Get a De-Icer – These are often small, floating heaters which keep the water hot enough to prevent the water from freezing over.

Turn off equipment

If you are expecting icy weather, you should turn off your fountains and ornaments. This is to prevent your water features from freezing up as this can cause water loss. Once the ice has melted, if the pond has an odour (like a stale smell) then do a partial water change and use a dechlorinator

If you need any further assistance, please contact us.

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