How To Choose The Best Koi Pond Filter

Why spend a mini fortune on your koi pond construction, pond decorations, and your koi fish themselves, when you neglect the engine that keeps the pond ecosystem running smoothly – your pond filter? Depending on the size of your koi pond, your filter has to match the workload that you require of it. Koi pond filters such as the Evolution Aqua Nexus 320 are kept up to date with new and current innovations designed to ensure maximum water clarity and keep ponds healthy and clean. Learn more about the ins and outs of filtration systems so you can understand better how to choose the best one for your pond.

Size Matters

The size of your pond makes a big difference in which filtration system you choose. The bigger your pond, the more capable your filter has to be in order to keep up with the workload. As a general rule, your filter must be able to process all the water in your pond 3 to 5 times per hour. That means if your pond is 1,000 gallons in volume of water, your filter must be able to handle around 3,000 to 5,000 gallons of water in an hour. If you have a large outdoor pond, the Evolution Aqua Nexus 320 is perfect for water volumes of around 7,000 to 9,000 gallons. Do note that the more fish you have in your pond, the more waste will need to be filtered, so it is better to get a filter with a higher rating than you think you might need based on a tank devoid of fish.

Stages Of Filtration

In every koi pond filter, there are two stages of filtration occurring. One is called biological filtration, and the other is mechanical filtration.

  • Biological filtration: the process of removing biological waste, such as ammonia, to maintain the balance of chemistry in the water and to eliminate unwanted microbes from your pond. This process uses a media substrate that encourages the growth of beneficial bacteria, which in turn convert ammonia (which is waste produce by koi) into nitrates, which can be absorbed by plants living in your pond. Alternatively, the process can be done by using ultraviolet (UV) light to kill off unwanted microbes like parasites and bacteria which may spread diseases to your koi. UV light filtration requires the water to pass through more slowly so that it can be exposed to the light for longer, so be sure to maintain a low pump flow rate if using this method.
  • Mechanical filtration: this is simpler than biological filtration, but just as important. It uses a physical filter to remove particles, such as algae and large pieces of food waste, from the water. An ideal filtration system has multiple layers of mechanical filters to avoid from clogging.

Filtration Capacity

A good gauge for the filtration capacity is that you should get a filtration system that offers two to four times as much filtration capacity as your pond volume.

For example, if you have a koi pond that is 1,000 gallons, you should look for a filter with a rating of at least 2,000 gallons. One thing to note though is that if your have many koi in your pond or your pond is in direct sunlight for most of the day, you should go for a filter rated 4,000 gallons for that same 1,000-gallon pond.

If you have a large pond, you should certainly consider the Evolution Aqua Nexus 320, with a filter rating of up to 9,000 gallons. You can easily purchase it online, as well as all your other koi care needs, at Everything Koi.