Pond Boss Forums AERATION Systems questions Fountain run times

Hey Folks!

New member here.

We have a newly dug pond.

Rectangular base, max depth about 6 feet and about an acre in surface area.

I have power at pond.

Boss lady wants a fountain so I will handle that.

But for aeration, how is best to approach that.

How do I know CFM, HP, number of stones, placement of stones etc.

Pond is 6’ on deep end, carries the depth about 65% on pond and then tapers to shallow.

Don’t know what type of system to buy, how often to run it, etc.

Don’t know if it is possible to over aerate?

Should I get a meter that measures DO?




All help is appreciated !!!!

Howdy, Jim, and welcome to the Forum!

In addition to all the advice you get here, check out the Resource Guide for aeration and see what vendor(s) are near you. (You can find opinions on some of them, and different aeration product brands here). When I added powered aeration to my ponds, the late Ted Lea of Forever Green (Vertex) here in Ohio was an invaluable source of advice and equipment.

One piece of advice from me - make sure you have excellent cooling for your compressor(s). I have a boxer fan sucking air (as cool as possible, from the North side of the enclosing building) that blows directly on my compressor. It has a separate timer to start it up an hour or so before the compressor starts each day. The combo have been running (seasonally, about 7-8 months a year) since 2008 without any problems.

Hello Theo and thank you!

When you do run your aerator, do you run it 24/7?

Is it possible to over aerate a pond?

Do you have a meter or something that tells you your DO and that might help you know how long to run the aerator?


Many thanks !

Jim

Firstly. The need or requirement of bottom aeration for just a 6 ft deep pond will depend a lot on water clarity.
Most people do not realize it, don't know about it, or don't accept the fact that most of the dissolved oxygen (DO) in the pond, lake or ocean is produced by algae (phytoplankton, periphyton) and submerged 'greenery'. Atmospheric oxygen does dissolve into the surface water by various ways of moving the water, but those methods do not produce the largest percentage of DO in a water body. Oxygen has a low solubility factor into water thus it dissolves very slowly into the surface water. Thus if the photosynthetic organisms can get enough incident sunlight (euphotic zone 1% of what was at the surface), photosynthetic plants will create DO where they are living. How deep of water they do that depends on water clarity. Read about it or look it up – see more below.

Secondly. Rather than spend a lot of money for a DO meter, I would buy or build a Secchi disk. However deep you can see the disk multiplied times 2 - 2.5 and sometimes 3 depending on the water turbidity, is how deep oxygen is being naturally created in the water body. 3 feet Secchi reading means oxygen is being created at the bottom in 6 ft to sometimes 9 ft of water. When the pond has 2-2.5 ft Secchi, IMO one does not need to have or run the bottom aerator. Fish kills should be very rare unless the water clarity is less than 12”-14". Then there will some concern of fish kill but the likelyhood is still quite rare for a pond just 6 ft or less deep. This because the anoxic no DO zone for a 6 ft depth pond is a small volume compared to the large volume of water in the epilimnion (shallow warm oxygenated layer). Thus the degration factor of anoxic water into the good water is quite low.

Thirdly. Normally when the pond receives “decent” regular wind exposure the wind action will naturally and regularlly mix good quality surface water down to around 6 feet deep, at least that occurs on all the ponds that I measure DO. Buy a DO meter and prove me wrong.

Fourthly. If you have an operational fountain (1hp) , that fountain by itself will adequately mix the upper water layer at least 1 foot deeper that the motor intake. Fountains do not mix water throughout large areas; normally the highly oxygenated zone is mainly in the vicinity of the fountain. Fountains mix their active water over and over dissolving more and more DO in the same water again and again near the fountain. Thus fountains create an area of high oxygen refuge in the vicinity of the fountain. Wind action does move aerated fountain water around into other areas of the pond. A shallow 6ft deep pond with a functional fountain and good wind action IMO should not need a bottom aerator. Wind action should easily in most cases mix oxygenated water down to around 6 ft deep. If you do not use supplemental water to keep the pond at full capacity, during dry, low rain periods with evaporation with some normal pond leakage, expect the deepest water depth during those periods to be just 4 ft to 5 ft.

Bottom diffusers are not really designed to actually add a lot of DO into the water by the bubbling action. Because A. Oxygen dissolves very slowly from inside the bubble into the water. B. Bubbles rise about 1 ft per second. Thus the bubbles are not in contact with the water long enough to get very much oxygen into the water. C. Bottom diffusers are designed to move lots of water cheaply by air lift technology to the surface from the bottom where the lower quality DO water gets degassed and re-oxygenated by mainly the phytoplankton surface zone activity.

IMO - With a pond only 6 ft deep you will have many, many more problems with weeds and algae than problems with low oxygen.

From the Internet
The Euphotic Zone
• Definition: The depth at which approximately 1% of surface light remains.
• Significance: It is the region where plants and algae can produce more energy via photosynthesis than they consume through respiration.
• Depth: In clear open ocean, it can reach up to 200 meters (656 feet), but in turbid lakes or estuaries, it may be only a few meters deep.

The Secchi Disk
• Function: It measures water clarity by determining the "Secchi depth"—the exact point where the disk disappears from view when lowered into the water.
• Usage: It is widely used by researchers and citizen scientists to monitor water quality, as lower Secchi depths often indicate high levels of algae (eutrophication) or suspended sediments.
• Procedure: To get an accurate reading, the disk is lowered until it vanishes, then raised until it reappears; the average of these two points is the Secchi depth.
Relationship Between the Two
While they measure different things, Secchi depth is frequently used as a proxy to estimate the euphotic zone depth:
• The "Rule of Thumb": As a general rule, the euphotic zone is estimated to be 2 to 3 times the Secchi depth.


Primary Sources of Dissolved Oxygen
• Photosynthesis (Major Source): Aquatic plants and microscopic algae (phytoplankton) are the primary producers of oxygen in most pond and lake systems. During daylight, these organisms use sunlight, water, and carbon dioxide to produce glucose, releasing oxygen as a byproduct directly into the water. In some productive systems, photosynthesis can account for approximately 89% of total dissolved oxygen revenue.
• Atmospheric Diffusion: Oxygen from the air naturally dissolves into the water's surface to reach equilibrium. This process is significantly enhanced by wind and wave action, which increases the surface area for oxygen to enter the water. In large lakes, atmospheric diffusion is often the main mechanism for oxygenation, though it is less efficient in small ponds sheltered from the wind.
Oxygen diffuses much slower into surface water than it does through air because water is denser, causing more molecular collisions that impede movement; it can be thousands of times slower, with estimates suggesting it might take years for oxygen to diffuse just a few meters in still water, but rapid mixing from wind, waves, and turbulence speeds up the process significantly by increasing surface area and mixing layers.

1. I run a varying number of hours depending on season and temperatures. Early Spring: 8 hours in the daytime. When the daytime air temps got hot, I switch to night time, 12 hours late Spring, 16 hours mid Summer, and 18 hours starting in September. When things cool off (October sometime), I go back to 8 hours at night until water temps get to about 50 deg F. Spring time startup, when water temp passes 50 deg F, is a ramp starting at 1 hour and adding an hour a day. (15 minute increments are generally recommended.)

2. Pass

3. As Cody mentions, I use a secchi disk (made from a mudflap, white electrical tape, and an old broomstick). The majority of the regimen listed above is attempting to avoid prior fish kills that occurred when I wasn't aerating that many hours (notably the bump in September).

Bruce Condello once stated that you aren't a real aquaculturist until you've killed your first million fish. I qualify.

P.S. Bill Cody is like E. F. Hutton - when he talks, people (should) listen.

Thank you, Theo!

Merry Christmas!

Mr. Bill

Thank you so much for the well explained advice.

You knowledge - and ability to relay that info - is superb.

I really feel like all I have right now is a hold in the ground with new well water in it

The water is very clear and I am 95% sure I could clearly aeee the Sechhi disk at the bottom of the pond, which is only about 5.25’ deep now.

I have no aquatic growth and do t really know how to get the “food chain” going.

I will continue to research and TRY to learn (and try to avoid the dumb tax).


Merry Christmas sir!

Hello folks!

Brand new pond.

About an acre and it will be (God willing) 7 feet deep. Pond is oval and carries that dept for about 80% of the pond.

Pond is just over 6’ now and the water is primarily well water we pumped in there.

The water is clearer than I would like and the pH appears to right at 7 according to some cheap test strips I have.

My guess is the DO is not very good.

The main question is - about how long should I run the fountain each day?

And what time(s) of day and/or night?

The fountain is 1 HP and much heavier than I thought it was gonna be.



Many thanks!

Jim and Jo

Fountains do little for aeration or mixing bottom and surface water.

If you put it in to look nice, run it when you can see it.

Okie doke

Yes, the boss wanted so there we have it.

I am slightly confused, however. All that I read, some of which is on this forum, is that fountains can help aerate a shallow pond, can reduce stagnant water, can help reduce mosquito larvae, help move the water around in a small pond - and - are aestheticly pleasing.

I am not a guy that leans toward the n’th degree - I just want a decent fish / swimming pond.

Thanks!

A fountain will do all of the things you listed ... just very inefficiently.

I agree with Theo's advice.

You are kind of asking how long you should run 50 electric hot plates to heat your home, compared to running a 98% efficient gas-fired furnace to heat your home.

The electricity to run a 1-HP air pump and good diffusers in your pond would add MUCH more DO to a much greater volume of water, compared to the fountain.

(I say this while liking the look of fountains on manicured ponds. However, the fountain should mostly be considered a "decorative" feature.)

The DO might be higher than you think, but to answer your question I would run the fountain enough during the day to keep the wife happy at a time of HER choosing, then run it from roughly 4 to 5 hours before sunrise to an hour after sunrise.

In your shallow pond, it might now aerate all the way down to the bottom, but it should aerate the upper 1/2 to 2/3 of the water column. Unfortunately the only way to tell for sure is with an O2 meter and those aren't cheap. I have one because I am in the pond business, and it has saved my butt numerous times, but for a residential pond owner it's not a "must have".

As for the water being clear, that is because well water is low in nutrients and has 0 phytoplankton in it. Wait a few months and see what happens. One thing you can do is go buy alkalinity test strips and test the water alkalinity. You want a reading over 40.