Choosing A Koi Pond Pump

Koi ponds need around 200 gallons of water for each fish and large ponds need powerful pumps. External pumps are quiet and efficient with heavy-duty motors. The best rule of thumb on pumps for koi is the larger the better, so shop for the largest affordable pump.

A heavy-duty koi pond pump circulates water 24 hours every day to keep the pond clean and to maintain a healthy environment for the fish. Koi pumps circulate oxygen to the bottom of the pond to benefit the fish and to prevent sludge. These pumps need to be non-corrosive, leak free, low maintenance, economical and durable.

Koi pond pumps should circulate and filter the pond water every 2 hours. A 1000 gallon pond needs a 500 GPH (gallons per hour) pump. With a waterfall, fountain or cascade, it will need a stronger pump to clean the water and run the water features. You can use two smaller pumps or one large pump for the pond and a second pump for high waterfalls.

External pumps are best for ponds over 1000 gallons. They are safe from leaks and shocks and are very efficient. You can use the formula below to determine the cost of running a pump.
amps X volts = watts
watts X 744 divided by 100 = KW hours per month
KWH per month X KWH cost (from your electric bill) = cost per month

To choose a suitable pump, consider flow rate based on the size of the pond, the amount of fish, plants and sun. If the pond has water features, consider the total dynamic head (TDH) required to deliver that flow rate. Head is the measure of resistance to the flow. For example, 20 head feet means the pump can pump water 20′ into the air. A 50 GPM/10’ pump can pump water 10 feet into the air and circulate 50 gallons of water per minute simultaneously. As head is increased, flow is decreased. You get maximum flow with minimum head. You can determine the TDH by adding static, friction and pressure and using that figure to select the most efficient pump with a 2 or 3 year warranty and long 3-prong grounded cord.

Sequence makes centrifugal pumps. Their 750 series is for ponds of 3000 gallons or less. The 750 has a fan-cooled motor, 8’ cords and 3 year warranty for around £250. The 1000 series is for medium pressure with ample flow for most ponds and is priced from £300 to £450. A self-priming version runs £550 to 600. Leaf traps can be purchased separately for £50 to £180.

PondTech pumps are self priming in six low head/flow rate models or in 3 medium head/flow rate models. All include large strainer baskets, low wattage and 8’ cords for £400 to £900.

Artesian produces industrial quality pond pumps for all types of water garden setups. They offer self priming and centrifugal pumps with maximum flow and good pressure. Cascade models are priced from £250 to £500 while Artesian and Artesian Pros range from around £400 to £900.

Due to the variety of models offered and the number of decisions that have to be made before purchase, choosing pumps for koi ponds can be challenging. You need to do your homework before shopping and be ready to ask lots of questions before buying.