Pond Boss Forums AERATION Should I aerate? Why Aerate?

I am a novice, and I know my ignorance is quite blatant when I ask this question:
Would I need to aerate a 3500 sq. ft. pond, and why? What does aerating do exactly?

A very simple question but details for a complete answer are very lengthy. Simply, if you want your water to be "fresher" or "healthier" overall during the year in the pond, then aerate.

A lot of things can determine if a pond needs aerated. Basically from my experience I think all ponds need enough bottom aeration to circulate the entire deep water basin or zone of the pond once every day or two. In every pond that I have dealt with that gets bottom aeration, the overall pond characterists usually appears "better looking" to me, but I know what signs to look for, many do not know what things to look for. A pond can still have lots of algae when the pond is aerated. Many of the improvements from aeration are not visible from above the water. I have sold hundreds of bottom aerators and give every customer a money back pond improvement guarantee; none have been returned, and never a complaint that the water is not overall better. But again aeration does not solve all your pond problems. It just improves the general overall conditions within the pond.

Ponds that may not need aeration are those that have a short water retention time or those which have a strong flow of spring water into the pond that creates mixing and a constant circulation. Ponds that are shallow and get a lot of strong wave action may only need aeration primarily only during July or August when winds are less and air temperatures are the warmest. Even these ponds could thermally stratify during these periods. Startification and DO loss for short periods on bottom sediments means death to most if not all the benthic processing animals.

Even a 5 gallon bucket of water will form a "filmy layer" or stagnant type of layer on the surface when no surface agitation or stirring occurs. A small bucket of water with 4 minnows, 3/4" long in my lab forms this filmy layer. Every two or three days, I need to splash the surface occassionaly to break-up this film. An air stone with small aquarium pump would do the job much better of constantly circulating and renewing the water and exposing it to surface air and bubbled air.

Atmospheric oxygen dissolves very, very slowly into calm, still water. Without agitation this film layer severely decreases or stops the ever present slow transfer of oxygen dissolving from air into the water. Surface agitation, such as wave action, water falls, fountains, and bubbling action all help to increase the oxygen transfer into water because more water surface area gets exposed to air. Some methods are more efficient than others at adding dissolved oxygen to the water.

Hundreds and probably thousands of biological and chemical processes or reactions occur in water. The majority of these reactions require dissolved oxygen (DO) as a stimulus or facilitator. When the oxygen is too low or depleted these activities slow down or often cease. Then, decay without oxygen begins and septic conditions develop which results in very decreased rates (20x-30x) of decompositon. Black sediments and septic gasses are indicative of decay with lack of oxygen.

If algae is able to grow all across the bottom of your pond then you probably do not need aeration. Algae growth on the pond bottom will produce DO at the mud water interface where oxygen is used and needed the most in the pond. However the bottom under the algae layer may be devoid of DO. Water above the algae will likely contain adequate DO.

The only way to know for sure how low the DO gets in your pond is to make some measurements.

Most pond owners do not test for DO and recognize low DO conditions by seeing dead fish, that are symptoms of low DO. Very few people ever see the massive numbers of bottom living animals that commonly die due to lack of DO above the sediment surface because these animals are small, some even microscopic, and never float to the surface like some fish do when they suffocate. These animals and bacteria are extremely important in processing and decomposing the organic particles that grow on or settle to the bottom. Without them the sediment layer builds up and accumulates. DO is a requirement of life for these animal processors. Bottom aeration helps and improves their survival.

Additionally aeration often results in creating currents or water circulations in the pond to help distribute and mix the water. This results in decreasing the amount of stagnant areas or pockets that develop due to their location. Stagnant areas can get a build up of concentrations of respiratory gasses which inhibit biological activity. This gradually results in degraded water quality. With increased water mixing, a larger percentage of the pond now gets renewed water with DO and the overall pond benefits which is often evident by "cleaner looking" fresher water.

As I said above, just because you have an aerator you do not need to run it continuously.
Aerators should be sized appropriately for the water body to produce adequate mixing and pond water turnover. Often one-half or one turn over a day is sometimes adequate for many ponds. This depends on pond size (volume), size of aerator and oxygen demand of the pond system.

Numerous other benefits occur due to aeration but I have rambled on enough about this.

I must say I do enjoy reading your posts Bill. It is like a nice fix between PB mag publications.

That is very imformative, thanks for posting that Bill.

Alternatively, PB is a nice fix in between Bill's posts.

THIS is why I think we need to archive some of this stuff.