Pond Aeration

This article is a little more focused on larger ponds, but some of the same principles applies in smaller ponds, where oxygen is concerned.

Ponds, Like People, Need Oxygen to Live

Dissolved oxygen (DO)is a the most important parameter to monitor in a pond or lake. Basically it is the amount of oxygen available in the pond water. A good rule of thumb for determining if your pond has enough DO is to measure it in ppm (parts per million). A DO level of 4 ppm to 5 ppm is typically the bottom thresh hold for most ponds.

There are numerous issues associated with low dissolved oxygen:

* Fish kills – most critical
* Noxious odors from anaerobic waste digestion
* Stratification – oxygen deficient layer of water on the pond bottom

What are the causes of low oxygen levels? There are several factors that contribute to low DO in ponds, including:

* Over abundance of algae and aquatic plants that consume oxygen at night
* High organic waste load
* Over population of fish

If these issues are a concern for you then a proper pond aeration system could be a solution. If you have a deep pond say 8 ft or deeper, you will most likely get more benefit from a bottom based diffuser system that pushes air to the bottom of the pond and allows it to bubble to the top. These systems allow for greater mixing of the water column and eliminates stratification.

If you have a shallower pond, a surface aerator like a fountain,would be a good option. They pull water from the top foot of the ponds surface and sprays it into the air. When the water splashes down onto the pond it creates an oxygen exchange at the surface and helps to aerate the top few feet of water.

Pond Aerators provide numerous benefits and include:

* Reduction and elimination of fish kills(due to low oxygen)
* Stimulation of beneficial aerobic bacteria
* Problematic nutrients are made unavailable
* Algae blooms are reduced due to the lack of available nutrients
* Prevention of turnovers and improved overall water quality
* Odors reduced

A good, properly sized pond aeration system is not cheap, but the costs for alternative treatments and maintenance work far outweighs the cost and long term benefits of aeration. It is highly recommended that you contact a professional to be sure you get the right system and that it is not undersized.

Visit this other pond aeration article for more details on the importance of a well oxygenated pond.

What do you think of waterfalls for aeration?

Bought a Oase AquaOxy 450 and installed it yesterday. I am very impressed. With the valves wide open the bubbling is vigorous. There are several nice things about this unit: it comes with tubing & aerators X 2. And it runs on 12 volts via a 25 watt transformer. I'll probably adjust the flow and location over time, but I'm very pleased with the product.

Bought it at WebbsOnline. Might be better prices around, but I couldn't find any.

I am a big advocate of cascading waterfalls. That said, your water losses go up with them.
For example; my 4' drop through many rocks produces a 2" loss daily through evaporation. When I by pass it and run the water through a 1" pipe back to the pond, the loss is only 1/2" a day.

That amounts to about 200 gallons a day savings by not running it. It looks funny when I bypass it, hen I am away or at work, it goes back on. It only takes a couple minutes to make the transformation.

The reason I bring this up is; when plumbing a waterfall, you might consider installing a bypass valve that allows you to cut off the waterfall without stopping the bio filter that feeds it. If I could redo mine easily, I would install this 1" bypass where it could not be seen and a simple turn of a valve is all that would be required to perform this function.

In Southern California, we are in a drought. My water usage goes from 38,000 gallons a month to a low of 7,000 gallons when the automatic sprinklers are off. So by bypassing my waterfall, my savings are 6,000 gallons a month. Wow, untill now I didn't realize just how much it wasted!!!

So enjoy your waterfalls, but use them wisely.

Dr. Dave,

1) lived in N. California during a 7 yr drought. Actually had ads encouraging people to shower together! I was young and thought that was a hoot. Lawns didn't exist. Fines were there for watering out of sequence so most folks just let them go.
2) converted 1/5 of our backyard into a garden. Converted the sprinkler heads in that section to drip irrigation. Works great.
3) Wow, I'm amazed at the evaporation rate you have. 2 in per day your pond goes down? And the change in water usage is amazing too.
4) I agree totally. I really wish I could bypass the waterfall, but with the aquafalls, I don't see how. The filter works by water coming in at the bottom and going though the filters and over the falls. When I redo it, I'm going to change to a different kind of falls and filter and will do as you say, i.e. make is so I can bypass the falls without losing the filtration.

nt agree

This is a really old post... what does "nt agree" mean? We here are not all hip to the abreviations used by todays youth.