Not every pond will need aeration, or adding air and circulation to the water, but every pond will benefit from it. There’s no question about that.
If you look around online, or even at some local pet or hardware stores you’ll find a ton of different aerators for small ponds or water gardens. There are so many that it can get really hard to choose which one to buy that will find your pond and needs just right.
In this post I want to share with you what I think are the things you should look for and consider when buying an air pump and system for your pond.
Fit The Aerator To The Pond
This probably goes without saying but virtually every aerator package will have some kind of rating or suggestion for a pond’s gallon size and this is the best reference you can use to fit the device to your pond. For instance in our small pond systems, the Pond Air 2 is rated for ponds up to about 1,000 gallons and 3 feet deep. Anything less than these numbers and you can be pretty sure the device will serve the pond well.
Of size and depth, I would frankly be more concerned about the max operational depth. If you go much deeper than this suggestion you run the risk of damaging the diaphragm and losing air. Certainly the overall operational life of the pump will be shortened. These diaphragms are easy enough to replace but you really don’t want to lose air creation at an inopportune time.
Assess Your Primary Needs
Pond owners use aeration for a couple of reasons. First, the added dissolved oxygen and circulation is really good at protecting fish. Second, this added air can also support beneficial bacteria so if one has algae or water quality issues, adding air may improve things. And finally, aerators are often used in the winter to control ice coverage on a pond.
Where fish are concerned, any added air is helpful. In one conversation I had with a Koi owner, we talked about aerators and she mentioned using two. One has lower air output, also called CFM’s and the other created quite a bit of bubbling at the surface, so much so that she couldn’t see the fish anymore due to the agitation!
So in essence, she used the device with higher air output during the winter, which helped protect the pond from freezing over, even in very cold weather, and used the more subtle air flow at other times of the year to maintain decent oxygen levels. Certainly if you don’t mind the added agitation of the water, you could use the higher CFM model year round.
CFM’s are useful for comparing models of aerators, and these numbers can vary widely, but generally what we’ve found is that more output isn’t always necessarily needed. If the device is rated (again for the pond size) and fit to a pond as suggested, it will do a good job of aerating. The saturation or holding capacity of the water will be affected more by temperature than anything and aeration should be looked at as a protective tool to guard against low oxygen levels. Running them consistently (24/7) will provide the results that most pond owners desire.
Apart from the things noted above, I think comparing things like manufacturer’s warranties, operational costs (which should always be quite low for small pond units) and the outright cost of a system is useful.
Most of the systems available today have warranties of 2 to 3 years which is very good and ideally most of these kits will last much longer than that. You may, after a few years, need to replace the diaphragm, which is the air creation part of the unit, and this is quite easy and affordable to do.
Most good quality small pond aerators, that will cover ponds up to 2,000 gallons or a bit more, will be priced well below $100. And systems targeted at ponds up to 16,000 gallons or so, will be available from several hundred dollars and up to a bit less than $500.
In the end, I’m not a big fan of making this process more complicated than it needs to be. The aerating kits you’ll find on the market today are all pretty good, and dependable. I would caution about cutting corners or getting too skimpy when choosing a unit. Simply make sure that the specs on the system exceed your pond’s needs and you’ll be fine.
And as always, if you have questions on small pond aerators, be sure to post those below and I’ll be happy to answer them.