One of the best ways to keep your fish safe and healthy during the winter months is by preventing your pond from completely freezing over. A pond de-icer saves you and your fish the heartbreak of “winterkill” caused by a combination of low oxygen levels and dangerous gases trapped beneath the ice as temperatures dip below freezing.
Before purchasing a pond de-icer, you should consider important factors like pond size, durability, cord length, and whether a submerged or floating de-icer is better. Our buying guide explores all these factors and offers our product recommendations at the end, such as the professional-grade stainless steel Kasco Marine Lake and Pond De-icer.
Pond size as measured in gallons and the severity of your winters determines the size of de-icer you need. As a basic rule of thumb, you need one watt of power for every gallon of water in your pond (e.g., 300 watts for 300 gallons).
Your pond de-icer should be durable enough to stand up to harsh conditions and the lower limits of temperature in your climate. Some models can weather -20°F while others struggle if temperatures dip below 20°F. Stainless steel stands up best to corrosion and cracking, followed by cast aluminum. While plastic is the least durable, it doesn’t get quite as hot as metal de-icers, which can damage ponds with plastic liners.
If you choose a floating de-icer, you may want to consider its appearance since it will be visible. Some de-icers are made to mimic natural stone, while others may stand out in the pond like a sore thumb.
Since most manufacturers advise against using an extension cord, a de-icer’s power cord length is an important feature. Cord length varies from 10 feet to more than 100 feet. Measure carefully from your power source to your pond before making a purchase. Wire-wrapped cords are desirable in harsh winter climates, since they hold up best in low temperatures.
Some models include a helpful LED display that shows you at a glance whether or not the de-icer is powered on. Check your de-icer regularly during the winter, since these products are somewhat notorious for their shorter lifespan.
While a de-icer doesn’t have a traditional thermostat that gauges temperature, many models offer a power-saving feature that turns the de-icer on and off as needed based on water temperature.
Budget de-icers for small tanks or ponds start at $40, but you should keep in mind that low-end models are notorious for lasting just one or two seasons. Mid-range models offer warranties, coverage for larger ponds, longer cords, and cost between $50-$100. Submersible professional-grade options meant for boats and large bodies of water can cost upward of $600.
A. If you’re already using an aerator to help oxygenate your pond, you may not need a de-icer unless your winters are very harsh, which is good news, since aerators are less expensive to purchase and run. Likewise, if you have a waterfall that runs during the winter, you don’t need a de-icer.
A. Position your de-icer in a shallow area of the pond that you can comfortably access for installation. Your de-icer reflects heat off the sides and bottom of the pond, so a shallow area allows it to work more efficiently.
Kasco’s Marine Lake and Pond De-icer
Our take: Professional-quality, stainless steel de-icer that can easily manage larger ponds.
What we like: High-quality materials and construction. Simple setup and instructions. Several power cord length options up to 100 feet. Able to maintain a 95-foot diameter ice-free circle of water.
What we dislike: More expensive than other options. Heavy to lift. Must be mounted rather than hung to prevent wire breakage.
Where to buy: Sold at Amazon
Our take: Affordable, attractive option that’s energy-efficient and great for ponds up to 300 gallons.
What we like: Natural-looking faux stone finish. 15-foot cord. Energy-efficient and keeps pond de-iced down to -20°F.
What we dislike: May only last one or two seasons.
Where to buy: Sold at Amazon
Our take: Durable, cast-aluminum construction that’s great for smaller ponds or tanks.
What we like: Efficient at de-icing ponds or tanks up to 600 gallons. Includes wire-wrapped 10-foot cord.
What we dislike: Some reports of units failing after only a few uses.
Where to buy: Sold at Amazon
Sign up here to receive the BestReviews weekly newsletter for useful advice on new products and noteworthy deals.
Noelle Ihli writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.
