Pond Air Pumps – How Different Designs Work Best

I guess to most people, the act of pumping air into a pond doesn’t sound all that complicated.  And in truth it’s not really, but there are a few basics that are good to know if you’re trying to get the best aeration system set up in your pond.

I don’t usually get too hung up on some of the components.  On the airline I do suggest going with self-weighted tubing when dropping the line into the pond simply because it’s easier to manage, sinks on it’s own, and it’s quite durable.  In other words, the benefits outweigh the costs.

Diffusers come in a several kinds of shapes and sizes.  Small ponds use air stones in most cases and these usually work pretty well.  Large pond aeration systems use some kind of rubber membrane to diffuse the air.  It might be in the shape of a tube, or a plate, but for the most part the air output and diffusion is good with either type.

The compressor or pump however is another matter.  This really is the backbone of any good aerator system and it just makes sense to get a really dependable performer to fulfill this important role.

In this article I want to talk about the most common types of pond pumps, how their designed, and where each type is best suited for use.  Certainly each one will work best in a particular setting so I’ll outline those differences in more detail.

Along with that, there’s an “in action” graphic (compliments of Gast Mfg.) to show how easy of these designs works internally.

In the pond aeration marketplace, you’ll find three main designs used for the compressors.  These include linear models, as well as rotary vane, and rocking piston compressors.  All are quite good, reliable, quiet, and efficient.  These certainly aren’t like your shop compressor in the noise department!

Linear Compressors

Linear compressors tend to be used most often, and are best suited to smaller ponds and those with shallow to moderate depths.  These pumps use an internal diaphragm to create air and you’ll see them used in ponds and aquariums of just a 100  gallons, on up to ponds of around a 1/4 to 1/2 acre.  In the case of these larger waters, the linear compressors are specifically used in shallow pond aeration packages where the depth is not much greater than 8′ at maximum.  

The design of this compressor does not allow for deeper water operation and exceeding the suggested max depth will usually result in damage to the pump or a shortened operational life of the compressor.

In terms of maintenance, the most common repair is the replacement of the diaphragm itself.  Usually this is easy to do with a simple plug-in and run exchange.

Rotary Vane Pumps

As the name implies, a rotary vane pump uses an internal array of plates or vanes that spin around a central axis.  These pumps do a very good job in large waters such as multi-acre ponds and lakes.  The key however is that rotary vanes will work best down to about 18′ of depth but not more.  

So while they do go deeper than linear compressors, they still have some limitations on operational depths.  

Rotary vane pumps tend to be a bit more expensive than other compressors and that may play a part in the fact that they aren’t as commonly used as the more popular rocking piston systems.

Our exclusive use of rotary vanes is with our shallow water, winter aeration system that uses diffuser tubing instead of a traditional plate diffuser.  The rotary vane works well in this particular setting where the depths are usually not more than 8′ and the goal is to protect larger sections of boat docks and other areas from ice damage.

Rocking Piston Compressors

For large ponds, of 1/4 acre and up to multi-acre ponds and lakes, the rocking piston compressor is the most commonly  used system today.  They represent a very solid and efficient compressor that can handle just about any pond situation, from shallow installations down to about 50′ of depth.  The tend to be more affordable than rotary vane compressors and because of this they are the most popular pump in use with pond aeration kits today.

The operational life of the rocking piston compressor will often run out to 7 years and beyond.  The only routine maintenance would involve occasional cleaning of the filter, and replacement of several rubber piston seals once these wear down and compression drops.  If the compressor is still running but not producing air, it’s a tell-tale sign that the seals need to be checked or replaced.

This type of seal replacement is pretty easy to do and the vast majority of users will do this themselves in 30 minutes or less.  

It’s a fortunate trend that many pond owners are now realizing that a good pond aerator will be critical to maintaining great fish health and vitality, as well as protecting them from low oxygen in the water during very hot weather.  

Along with this, when someone is trying to restore a pond using natural methods, such as beneficial bacteria supplements, an aerator will help to improve the performance of these microbes as they tend to be aerobic and thrive in higher oxygenated water.  For ongoing cleaning, balancing, and limiting the build up of organic muck and sludge, whether it’s by a naturally occurring bacteria or one that’s supplemented, an aerator will serve and support this work very well.