Pond Aerators

OK, let's talk about pond aerators for a bit.

There's no doubt that a pond requires oxygen in the water.

The question is how we get it there and how we keep it there.

As in many things about a pond, it all depends on your individual pond and how you've set it up.

Small Ponds

If you have a smallish pond (12'x8') and you have a waterfall, then you really don't need pond aerators.

If you have a small plastic in-ground pond without a pump, and have followed the recommendations for oxygenating plants, then you don't require pond aerators either.

If you have either of the above and a very heavy load or population of fish, then you may very well need some extra oxygen in the pond.

Heavy Loading

And that points us directly to the reason we might add pond aerators - if we have heavy loads of fish. A pond with plants and a few fish won't require extra oxygen but if you load up on the fish, you need to find a way to increase or maintain high O2 levels to keep the fish alive.

Use pond aerators during the winter to keep ice from forming and maintain oxygen levels for the overwintering fish. You can keep fish alive in 18-inch deep ponds in a zone 4 if you provide winter aeration to keep a hole clear in the ice.

Some "serious" pond aerators. :-)

Choosing Pond Aerators

In choosing pond aerators, understand there are two basic types. The first is a Fountain and the second a bottom-lying system or Diffused Air System.

Fountains put a spray or jet of water into the air and can be quite artistic. They usually only aerate the top few inches of water and do not add much circulation from or to the bottom of the pond.

Diffused air systems lie on the bottom of the pond and push water upwards. This not only aerates the top surface (where all oxygen exchange occurs anyway) but it mixes the water and increases the O2 levels at all depths. During very hot weather, a Diffused Air System will keep your fish much happier.

A Diffused Air System is typically much cheaper to run as smaller electrical motors can be used to move the same amount of water. Note that Diffused systems can either be water pumps moving water or air compressors producing air bubbles that roil up the water.

Air Compressors

When it comes to air compressors, you have even more choices in pond aerators:

Linear compressors are extremely energy efficient and reliable. They have low pressure capacity so are mostly used in shallow ponds (less than 8'). This is the design of compressor you'll find in aquariums and small ponds- a low pressure but high volume of air.

Diaphragm Compressors are very high pressure, but low volume of air. Use these for very deep pond aeration and de-stratification (mixing water levels from top to bottom) You use these on deeper fish ponds but not usually in home ponds.

Rotary Vane Compressors are medium volume, medium pressure compressors and you'll buy one of these if you have a huge pond or backyard lake that is less than 18' deep.

Rocking Piston Compressors are for the serious lake owner with depths beyond 40'. If you have one of these in your backyard, you don't need this website- you need to talk to a Fisheries and Oceans person. :-)

Regenerative Blowers are for extremely high volume, low pressure aeration of tank system and shallow ponds. This would be a commercial pond aerators application for raising many fish in a small area.

So what are we looking at in the backyard water pond? What Do You Actually Need

If you have a waterfall, you likely don't need a pond aerator unless you have too many fish in the pond (sign - fish gasping at the surface of the water indicates lack of oxygen)

Unless you like the look of bubbling water. :-) Or you want to aerate a very small pond - particularly during the winter to keep a patch of ice clear for the fish.

Shopping Resources for Pond Aerators

Pond aerator options here