Pond pumps, aerators, fountains

[Robert Micheal]

Hey everyone,


I know this forum is mostly focused on aquarium setups, but I figured some of the monster fish keepers and outdoor pond guys here probably have experience with pond aerators too. I’ve been working on improving oxygen levels and circulation in a larger outdoor pond setup, especially with warmer weather coming up. A few people recommended adding dedicated pond aerators instead of relying only on waterfalls and pumps, mainly to help with stagnant areas, algae control, and overall water quality for bigger fish. While comparing systems, I found this collection that actually explains the different aerator styles pretty well:
https://www.protopond.com/collections/aerators

They’ve got bottom diffused aerators, floating aerators, and even solar options for larger ponds. I was mainly looking into setups for ponds with heavier bio-loads and larger fish.
From what I’ve been reading, a lot of experienced keepers say proper aeration becomes even more important once you start keeping larger fish or running heavily stocked systems. Some hobbyists also mention that improved circulation helps reduce sludge buildup and keeps oxygen levels more stable during hot months.
Curious what everyone here runs on outdoor ponds or monster fish systems:

• Diffused aeration or surface aerators?
• Any noticeable improvement in water clarity or fish activity?
• Do you keep aerators running year-round or only in summer?

Would appreciate hearing some real-world experiences before I settle on a setup.

 

[jjohnwm]

...by the time fish are surfacing, oxygen has likely been low for hours.

I'd love to hear an explanation for this ^ statement, because it just doesn't sound reasonable. Oxygen is required constantly, and I would expect the lack of it to become apparent almost immediately. It isn't analogous to poor nutrition, which causes problems that gradually come to light over weeks or months. A lack of sufficient oxygen will affect an organism immediately, right now! Fish removed from a well-aerated, well-oxygenated aquarium and placed into a bucket for temporary confinement or perhaps transfer, can if overcrowded and/or overheated begin gasping at the surface within a very short time...certainly not "hours".

I would suspect that part of the problem is that old bugaboo: overcrowding. Personally, I keep my fish in lightly stocked tanks and ponds, such that a power outage is not immediately followed by fish deaths due to lack of oxygen. Aquarists today always seem to need one more fish...and this results in crowded aquaria that are totally dependent upon artificial means of aeration, filtration and other forms of water management. Then, when these artificial methods are interrupted, disaster ensues.

Referring to ponds raises another question: what exactly is meant by a "pond"? People smugly talk about "growing out" fish in an aquarium and then moving them into a pond when they are large. Then they show a picture of the "pond"...and it's a puddle that can be stepped across easily, or a small kiddie wading pool better suited to bathing a dog. Calling a container holding X gallons of water by the grandiose term "pond" does not confer magical fish-keeping qualities upon it. It's still X gallons of water.

My single small outdoor pond is a cavity dug into the earth, waterproofed with an EPDM liner...and that's it. It has a light stocking of fish, a heavy growth of plants...submerged, floating and emersed...and a maximum depth of perhaps 36 inches in the center. I have toyed with a cheap solar-powered pump which did not last long, but that was strictly an experiment in aesthetics. The fish have never displayed any apparent signs of oxygen deprivation. In any case, the pump only functioned during sunlight hours, whereas all those evil oxygen-consuming plants engaged in their heinous activity during darkness, reverting to producing oxygen rather than consuming it before the pump ever got going in the morning...just as they do in nature...

Being an inground pond, mine has its temperature buffered and moderated by the surrounding earth. It will never warm up to the point where oxygen becomes a concern, at least not with the stocking it has. In fact, the calm water...which the worryworts among us would characterize as "stagnant"...is several degrees cooler at the bottom than it is at surface, and during hot weather the fish tend to stay in the depths. They make periodic feeding sortees to the surface but spend most of their time deeper...just as they do in nature...

Contrast that to an above ground "pond" like the several stocktanks in which I raise fish outdoors during the warm months. These tanks are also "stagnant", and while they undergo temperature stratification, they do not have the protection afforded by being dug into the ground. Surface temperatures can rise far higher than the inground pond ever experiences. Warm water extends deeper down, and in any case they are only around 22 inches in depth. Water temperatures in even an 8-foot round tank can vary as much as 12-15 Fahrenheit degrees in the course of 24 hours. These tanks are also heavily planted and lightly stocked, but they are much closer to the edge of disaster at any given time. They require shading from the afternoon sun during the height of summer...and I'm talking about summer in Manitoba, not California or Florida.

Fish behave in these tanks the same way they do in the dug pond; they spend time near the bottom during the hottest periods, approaching the surface in mornings and evenings...much like they would do in nature. No gasping, no distress.

Aeration added to these tanks must be approached very carefully. Simply tossing in an airstone or a sponge filter...as I originally planned to do...can lead to disaster. Destratifying the water with aeration produces a uniform temperature throughout, top to bottom, and that temperature can be far too high at midday in full sun. I have had problems with several species that simply could not do well at these temps, which can approach or exceed 80F easily and sometimes hit 90F. As non-intuitive as this may sound...the only solution is to discontinue aeration and circulation and allow the water to stratify again by temperature, allowing the fish to find their comfort level...much as they do in...well, you know.

Oxygen dissolves in water naturally; aeration will obviously increase the speed at which this can occur, but there is much calm water in nature that is full of healthy fish. How can that be?

If you love gadgets and tech then you can play with it all you want, and it can absolutely improve aspects of fishkeeping...but that doesn't mean it's necessary, nor even always desirable. If a reliance on tech support encourages you to create an unnatural overcrowded system that falls apart when the power goes down... that's not a good thing.

 

[danotaylor]

Summer: higher oxygen demand, so stronger or longer aeration

Oxygen demand is relative to metabolic processes in living organism. Temperate of the environment relates to availability not demand. The warmer the water the less O2 carrying capacity it has, resulting in a lower DO level.
What jjohnwm said about pond style and temperature fluctuations has tremendous relevance in figuring out each individual pond scenario.
The more biological processes, including waste breakdown, and consumption by algae which is more prevalent in warmer months, results in a further decrease in availability.
What am saying is that as the pond water warms in the summer O2 consumption increases reducing already lower DO levels d/t reduced O2 carrying capacity of warmer water.
Constant surface agitation together w waste removal will help maintain sufficient O2 levels in a pond <3’ deep. In deep ponds it is dependent on the amount of rotting waste in a static water volume as to what and how to achieve biological stability.
If you search “Inspired By Nature”, a natural pond management company that operates out of Ohio, there loads of great, science based, data on this subject

 

[danotaylor]

Robert any suggestion without knowing your actual pond set up or plan is a shot in the dark.
Please tell us about your actual pond, or the plans you are working on the installation.
Geography including seasonal temp variations, surface area & depth, and stocking density are all crucial factors in working out the answers to your questions.

 

[jjohnwm]

Good points ^ about oxygen demand vs. availability. The focus of this thread seemed to be on fluctuations throughout each day; mention was made of fish displaying distress in the morning, suggesting that the oxygen consumed during darkness by algae and higher plants dropped the overall oxygen levels below what the fish needed. Posters refer to having observed this multiple times; assuming that at least some of those posters are human beings and not bots, I guess this can be a concern.

While the plants produce oxygen during the day, the fish are most active and require the most oxygen at those times as well. At night, the plants revert to using oxygen...but most fish are at their lowest ebb in activity, so their utilization is reduced to its minimum levels as well. Of course, some predators are most active after dark...and many of those are air-breathers like many cats, lungfish, etc. so perhaps this is an evolutionary response to those horrid "stagnant" waters that are so creepy, but maybe it's also an adaptation to facilitate activity when the water's oxygen content is lower?

Another thing to consider is that shallower and smaller bodies of water...like our pitiful "ponds"...will exhibit greater temperature swings more quickly. The large changes I mentioned in my earlier post...cooler at night, warmer at midday...would also work to increase the oxygen-carrying capacity of the water after dark, when the oxygen production by plants has reversed to consumption. So we have fish competing with plants for the oxygen that is present after dark...but fortunately the oxygen carrying capacity of the cooler water is greater and the lower activity level of the fish decreases their need. Fortunate coincidences abounding. You'd almost think that the whole system evolved to work that way.

Oxygen requirements will vary from species to species, of course, and it's reasonable to infer that demand will be greatest when the fish are kept at the optimum temperatures for their species since they will then be most active. I don't think it's coincidental that Goldfish and Koi have been bred for centuries; as a species they are active and able to remain healthy over a very wide range of temperatures. I can put Goldfish outdoors at least a month before "tropicals" and leave them out at least a month longer in the fall.

They're not adaptable and easy to keep because they have been bred in captivity for so long; rather, they have been kept for so long because they are adaptable and easy to keep. Mine will display breeding activity as soon as water temperatures reach around 60F in my basement, and they continue to breed like mice after they are taken outdoors and send the summer living in a "stagnant" weed-filled pond. The only time they are seen "gasping" at the surface is when they are competing to hoover up the pellets I occasionally provide as food...and those feeding frenzies are equally enthusiastic whether the pond is at 60F or 85F. All without artificial aeration, circulation or filtration.

Don't these dang fish know they should be choking, suffocating, gasping their last? I'd better not let them read this thread, it'll scare 'em to death. Ignorance is bliss...and I tend to trust what I see with my own two eyes in the stock tanks and ponds in my back yard, as opposed to what I see on the internet.

 

[danotaylor]

Fair comment about personal observation for sure.

Fortunate coincidences of evolution…hmmm….not sure about that personally. Seems like more of an intentional design feature to me

On the OP’s other thread regarding pond related questions I requested info on geographic location (seasonal temp variations) pond size, surface area, depth and proposed or actual stocking. All of these data points are essential to work out the answer to send questions. Otherwise information being offered is very general and nonspecific to the question.

I did suggest checking out Inspired by Nature’s website as the bloke who runs the company has been successfully managing ponds over a considerable period of time. The info on his site has been time tested & proven in his business practice, the longevity of which is a testament in itself to his long management practices

 

[Robert Micheal]

Robert any suggestion without knowing your actual pond set up or plan is a shot in the dark.
Please tell us about your actual pond, or the plans you are working on the installation.
Geography including seasonal temp variations, surface area & depth, and stocking density are all crucial factors in working out the answers to your questions.

i want to install for large fountain

 

[Robert Micheal]

Hey everyone,

I’ve been seeing more pond owners adding pond fountains lately, and honestly they seem to offer more benefits than just decoration. Besides making a pond look better, they can also help improve water circulation and increase oxygen levels, which is useful for keeping the pond healthier overall.
Floating pond fountains especially seem popular because they work well for different pond sizes and can help reduce stagnant water areas. Some people also use decorative spray patterns and lighting features to improve the appearance of their ponds during the evening.
I’m curious if anyone here has experience using a pond fountain long term. Did you notice any difference in water clarity, algae growth, or general pond maintenance after installing one?

 

[willaims]

That’s interesting to hear. I’ve been considering adding a pond fountain mainly for better circulation and to help with algae control, so it’s good to know people are seeing real benefits from them.
Your point about oxygen levels and stagnant water makes a lot of sense too, especially for larger ponds.
By the way, where did you buy your pond fountain from, and what type are you currently using?

 

[Robert Micheal]

I’ve been looking into a few different options recently and mostly checking out floating pond fountain systems because they seem easier to install and work well for both aeration and water circulation.
I found some really nice pond fountain setups here while researching different styles and spray patterns:
https://scottaerator.com/collections/pond-fountains
They have several floating pond fountain options for different pond sizes, and some of them also include decorative spray designs and lighting features.