Aeration is a very crucial element in a koi pond. Every living thing in the pond requires a constant supply of oxygen. The koi, plants and even the bacteria in the filter need ample oxygen. In this article, I will discuss the best and most effective way to add oxygen to your koi pond.
The most popular method of adding oxygen to a koi pond is a waterfall. Most every koi pond built has some form of a waterfall feature. They are added mostly for their look and sound. Most think they are aerating their koi pond with the waterfall as well. And they are, but it might surprise you how little a waterfall aerates a koi pond. Aeration takes place though oxygen exchange. Anytime water and air come into contact, oxygen exchange takes place. The greatest amount of contact the water in the koi pond will have is on the surface. The reason a waterfall will add oxygen is because it breaks the surface and helps circulate the water on the top. The deeper the water from the falls penetrate the surface, the better the aeration.
The best way to aerate a koi pond is to constantly draw water from the bottom of the pond and return it to the top. This takes the poorly aerated water at the bottom and sends it up to come in contact with the oxygen at the surface. Constant circulation, 24 hours a day, is needed to maintain proper aeration in a koi pond. That is why a bottom drain is so useful in koi ponds. They not only remove the dirtiest water from the bottom, but they also pull the water with the lowest oxygen content out of the pond so it can get aerated when it is returned at the surface. Koi ponds that only have a skimmer and no bottom drains will always have problems with circulation and aeration. The water at the bottom of the pond is never circulated up to the top and has poor oxygen saturation.
Another easy way to aerate a koi pond is to use an air pump and air stones. The air stones are placed at the bottom of the koi pond and they create a rising column of air bubbles. Like a waterfall, the bubbles themselves don't add much aeration, but what they do is create a water column bringing water from the bottom, to the top where it can get aerated at the surface. So you improve aeration and circulation at the same time!
Air stones are also an easy way to temporarily add a boost of oxygen to your koi pond in the summer months. As the water warms up it is unable to hold as much oxygen. So you will want to give the koi as much oxygen as you can. A small air pump and a few stones are a quick easy way to vastly increase the oxygen levels without performing any major construction on the koi pond.
You can also combine the bottom drain and the air stone and get an aerated bottom drain. These are my favorite things to use in koi pond construction. The aerated bottom drain uses an air diffuser instead of a dome lid. So now you have a rising column of air directly over the bottom drain. This will create a current of water flowing towards the drain, increasing the distance it will collect waste along the bottom of the koi pond. So with this one item, you have improved filtration, circulation and aeration, talk about killing three birds with one stone! Every high-quality koi pond should utilize an aerated bottom drain. If you want to save a few bucks, you can accomplish the same effect by simply placing one or two of your air stones on top of a regular bottom drain dome. Either way, your koi will thank you.
Fluid bed filtration technology is another great way to aerate a koi pond. This involves sending air into a basin filled with bio media. The air rolls and tumbles the media in air bubbles. This provides a highly oxygen rich environment for the media to grow bacteria. Also, the tumbling media remains clean of debris. All bio filters work best with highly O2 saturated water and clean media. The fluid bed is the best at providing this.
Lastly, a well-placed spray bar can be an effective tool for aerating a koi pond. These use a high power spray to greatly agitate the surface of the pond. Creating loads of deep penetrating bubbles. The koi will love playing in the bubbles as it can create a strong current and high oxygen saturation.
Aeration is one of the most important aspects of koi keeping and also one of the most overlooked. Every living thing in the pond need high levels of oxygen, especially during the warmer months. Just adding a small waterfall simply won't be enough for most koi ponds. There may be enough oxygen for the koi to survive, but they won't thrive.