Pond Water Pumps

A Pond Owner Reader Submission

July 10, 2013
Dear Pond Owner Magazine,

I have been reading Pond Owner Magazine since a friend told me about it a few months ago. I’m glad to have found such an informative magazine that covers literally every pond subject from planning to maintenance. Now I send customers to Pond Owner and they all think its great.

The reason I am sending this letter is to clear up a couple of misconceptions that customers have been mentioning more and more often. The first is the comparison of diaphragm type pumps vs. bellows type pumps used in aeration windmills. The second concerns the best depth to install a diffuser in a pond.

On Windmill Water Pumps I sell Superior Windmill and Koenders Windmills products. I chose these manufacturers based on their reputation, service, product quality and the fact that they have been in business for many years. They both offer great products at competitive prices and will be around for a long time to back those products up.

Superior and Koenders both use diaphragm style air pumps on their windmills. There is a good reason why the two leading manufacturers of aeration windmills chose to utilize this type of pump. Much research time and money have been spent developing the pumps used in these mills. Superior and Koenders use pumps of similar construction that differ in details such as valve design, diaphragm size and length of stroke. Both companies have settled on these designs through hard testing and much field experience.

It would be relatively easy to design an air pump to aerate ponds if they all were the same size and depth. In reality no two ponds are the same. Therefore, these companies have designed a pump that works well in the varied sizes, styles and depths of the ponds found throughout the world.

The two most critical specifications in the aeration business are Volume ( cfm ) and Pressure ( psi ). While it would be straight foreword to build a pump that performs each task well, building a pump that excels at both gets a lot more complex. Now add the fact that this pump has to be able to perform in light as well as strong wind conditions, extreme changes in temperature, twenty four hours a day, year after year, then you begin to realize just how complicated this task is.

The amount of pressure that an air pump produces is directly related to how deep the diffuser can be installed in the water. One pound of pressure is required for every two feet of water depth that the diffuser is submerged in. The pumps on the Superior and Koenders windmills are capable of aerating to the depth of 40 feet without volume reduction. When the diffuser is submersed in 40 feet of water these pumps still produce the advertised volume of air. Also, both companies advertise volume figures conservatively at 9 mph wind speed.

One manufacturer is overstating the benefits of a bellows pump and spreading erroneous information concerning the correct depth to install a diffuser in a pond. The Canadian Department of Agriculture,CDA and Agri-Food Canada have done enormous research on the aeration of ponds. According to the CDA studies, the best location for the diffuser is on the bottom of the pond. This research is backed up by years of field experience as well. This is not to say the diffuser needs to be installed in the mucky bottom. The diffuser should be installed in a protective bucket to prevent the stirring up of sediment. Placing the diffuser on the bottom not only aids in the release of contaminant build up but also prevents pond stratification.

Of equal importance is the introduction of oxygen to the pond bottom promoting the growth of beneficial bacteria (aerobic bacteria) which competes with anaerobic bacteria (bad bacteria) for the food source. The aerobic bacteria eat nutrients 30 to 40 times faster than anaerobic bacteria. This simply starves the anaerobic bacteria to death without any harmful side effects when the diffuser is placed at the bottom.

When a diffuser is installed at 2/3 the depth of the pond, as is advised by one windmill manufacturer, the benefits from aeration never take place near the bottom of the pond .Although the top layer of the pond may look healthier, the problems at the bottom are allowed to continue along with harmful consequences.

Bellows style pumps used by some manufacturers are incapable of pumping the required volume of air at normal average pond depths. The capabilities of this style pump are drastically reduced with every additional foot of water depth resulting in favorable results only in shallow water. This is why one manufacturer selling a bellows style pumps recommends placing the diffuser 2/3 the depth of the pond.

In my opinion Koenders and Superior Windmills are the two best wind driven aerators in the world. When someone builds a better product at a competitive price, you will find it on my website because I will be selling it. Thank you for your time.

Have a windy day,
Terry Miller