Pond Aeration

Hi,
I'm thinking about setting up a 450 gallon (1700L) pond. Obviously, it will be a fish pond. Now, I understand that pond aeration and/or oxygenation is extremely important in ponds. I was wondering if I would be fine with a pump and filter, acting as a waterfall, that would rotate the ponds water every hour or so and would aerate the pond, and having that on only during the day. Alongside that I'd have an air-stone and pump probably. Basically what I'm asking is, would I be good with no aeration during the night, or not?

 

Surface agitation is the important factor, air stones have their place, but are no where near as useful or effective as breaking surface tension with a water pump. I would say ypu could get rid of *some of it at night, but if you have plants in there as well, your 02 levels might drop a little low since they also use O2 at night. Of course this obviously depends very heavily on stocking and temperature. The more fish and warmer the temperatures the more crucial gas exchange becomes.

 

I tested 3 setups a while back. An air stone, a wave maker pointed at the surface, and a pump on the bottom of the tank shooting water upwards.

The air stone and wavemaker were about equal but the air stone required around 7 times less power while the wave maker had to turn the surface of the tank into whitewater. The pump was the poorest performer by far.

The wastewater industry, where roughly 50% of their operating cost is aeration, switched from surface aeration to bubble aeration a long time ago. Their studies also found that bubble aeration was more efficient.

 

I tested 3 setups a while back. An air stone, a wave maker pointed at the surface, and a pump on the bottom of the tank shooting water upwards.

The air stone and wavemaker were about equal but the air stone required around 7 times less power while the wave maker had to turn the surface of the tank into whitewater. The pump was the poorest performer by far.

The wastewater industry, where roughly 50% of their operating cost is aeration, switched from surface aeration to bubble aeration a long time ago. Their studies also found that bubble aeration was more efficient.

The problem is an airstone cant move the surface water the same way in a pond as it can in a tank with vertical walls forcing the flow in a specific direction. I definitely agree aeration is vastly superior in controlled situations, i don't really think an outdoor pond quite fits the bill. Of course placement and shape of the pond are pretty big factors with my line of thinking.

 

I've always heard that big fish farms use airstones, but that may also have to do with the way they water change idk.

However, LRBRETZ doesn't use ANYTHING in most of his tanks but plants, and Prime Time Aquatics mainly only uses air powered sponge filters, so to say that air isn't good enough for a pond doesn't sound right.
I get that you are saying aquariums are different than ponds, but air rises in water and therefore circulates it. The air bubbles agitate the water surface, and create more surface area for gas exchange. I dont have a fluid dynamics degree, but i dont see that the sides of an aquarium affect whether the surface is agitated enough to exchange oxygen. Maybe the exchanged gas isn't circulated throughout the water column, but other than that, I dont understand why the shape of the container affects the gas exchange.
(I am not an expert, so I could be totally wrong.)

To OP: I think the waterfall could be turned off, but I would leave the air stone on all night. What are you wanting to turn it off anyway?

 

Im not saying it won't work, I'm saying out of the options, it is the least effective at surface agitation. Realistically it doesn't take much surface agitation for decent gas exchange, especially outside with the advantage of wind, unless it gets hot.
In a tank, an airstone is usually on the bottom along a side where as the water rises up, it is forced out from that spot along to the rest of the tank with more directional energy to the ripples can travel further than beimg somewhere in the middle of the pond where it would just be a weak force in all directions. I guess overcoming surface tension further out from the airstone is easier done in a tank compared to a pond. I'm just erring with caution considering you have a lot less control over variables outside than inside.

 

Im not saying it won't work, I'm saying out of the options, it is the least effective at surface agitation. Realistically it doesn't take much surface agitation for decent gas exchange, especially outside with the advantage of wind, unless it gets hot.
In a tank, an airstone is usually on the bottom along a side where as the water rises up, it is forced out from that spot along to the rest of the tank with more directional energy to the ripples can travel further than beimg somewhere in the middle of the pond where it would just be a weak force in all directions. I guess overcoming surface tension further out from the airstone is easier done in a tank compared to a pond. I'm just erring with caution considering you have a lot less control over variables outside than inside.

Ok. That makes sense. I must have misread your original comment and thought you meant that it wasn't effective.

 

My pond is circular with sloping edges. I do get the fact that aeration is superior. It's just a little far from any power source and I'm looking towards solar at the moment, hence the question. I know pond fish take oxygen by the truckload, and I was wondering, if you managed to store enough oxygen during the day, would it take you through the night or no? Thanks for all the answers.

 

The problem is an airstone cant move the surface water the same way in a pond as it can in a tank with vertical walls forcing the flow in a specific direction. I definitely agree aeration is vastly superior in controlled situations, i don't really think an outdoor pond quite fits the bill. Of course placement and shape of the pond are pretty big factors with my line of thinking.

Bubble aeration doesn't work via surface agitation. >95% of the oxygen transfer from a bubble plume is from the bubbles.

There are natural bodies of water as well as semi-natural ones (reservoirs) where dissolved oxygen levels are artificially boosted by bubble aeration.

Bubble aeration isn't used if the bottom is soft due to scouring.

From my experience measuring dissolved oxygen in aquariums, it depends greatly on stocking levels. Toss in a few more variables and it's difficult to know without actually measuring. I can tell you that a filter or merely breaking the surface often isn't enough. Aquarium Co-op came to the same conclusion. Strange how everyone with a dissolved oxygen meter says one thing and everyone who doesn't says another.

 

Typically you won't stock a pond as heavily as an aquarium, and typically you are going to have more vegetation in a pond, and typically a pond's surface-area-to-depth ratio is much higher. These all affect your O2 levels, in addition to artificial aeration methods. For instance, my little 110 gallon deck pond had 4 2-inch goldfish in it all summer...that's all I would ever stock in that tank... so that's roughly 27 gallons of water per fish. Coupled with the surface area being 3'x4', and a ton of living plants in it, both submerged, and floating...plus algae growing on the sides (something else not present in glass aquariums, typically). It's unfair and unrealistic to presume that aeration in a pond works the same way as aeration in an aquarium. Notice (and this was intentional) my use of the word "Typically." If you're going to put 40+ goldfish in a 450 gallon pond, then obviously you would need something additional. My personal feeling with an outdoor pond it to lean towards ease rather than work. My recent upgrade to 340 gallons..I'm still only going to put 9-10 fish in it.

 

I'd be going for like, 10 - 15 goldfish. I've looked into koi and I think its a no, but I'd like to talk with my LPS (if that's a thing(Local Pond Shop)) before completely shunning that idea.

 

Hey everyone I'm trying to start a small patio pond in Massachusetts, this is my first one so couple questions? does it need a filter if I also have a solar powered air pump? I'm only doing plants for the time being and maaaaaybe some cherry shrimp from my 10 gallon once it's established. also if I add the shrimp are there any ways to safe guard the pump without obstruction?

 

You can chuck a sponge in the front of the pump if there's space, that works. No cherries, I'd go ghost shrimp instead, they're hardier when it comes to temperature.

EDIT: Oh, sorry, air pump! I would recommend getting another pump to circulate and filter the water so it doesn't become to stagnant. Solar ones are anywhere from $20 - $100.

 

Okay since we haven't really come to a conclusion, can anyone at least tell me how to make a DIY dissolved oxygen tester (if it's possible) so I can see for myself?

 

Are you in a tropical or cold climate area?
If your in a warm area like I am you have to remember the warmer the water the quicker the oxygen depletes, I would suggest you leave the pond filter on and air stones on all the time to be honest....find a way to get a power source to it, not solar.
Puttin fishes outside is a fun experience I'm going through as well.

 

It's subtropical, so at the ridiculously high absolute maximum, 40 degrees Celsius (104 Fahrenheit). But usually only 30 degrees Celsius (86 degrees Fahrenheit) in summer. I have read that you can put ice in milk cartons and then put them in the pond to cool it down. In winter it usually only gets as low as 10-ish degrees Celsius (50 Fahrenheit) and doesn't freeze over. The average temperature is about 20 degrees Celsius (68 Fahrenheit). But it'd be good if someone could give me an answer to my previous question.

 

It's subtropical, so at the ridiculously high absolute maximum, 40 degrees Celsius (104 Fahrenheit). But usually only 30 degrees Celsius (86 degrees Fahrenheit) in summer. I have read that you can put ice in milk cartons and then put them in the pond to cool it down. In winter it usually only gets as low as 10-ish degrees Celsius (50 Fahrenheit) and doesn't freeze over. The average temperature is about 20 degrees Celsius (68 Fahrenheit). But it'd be good if someone could give me an answer to my previous question.

I was just reading about them and I do not think it is possible to d.i.y that one...

 

Yeah, I did a look around and had no luck. Someone told me that karbonate hardness is linked to oxygen levels though, anyone know about that?

 

Yeah, I did a look around and had no luck. Someone told me that karbonate hardness is linked to oxygen levels though, anyone know about that?

It's not. There's a relationship with CO2 though.

 

Can you buy dissolved oxygen test kits? If so, what brands do you think?

 

Can you buy dissolved oxygen test kits? If so, what brands do you think?

Yeah, but I don't think they work that well. It's a parameter where electronic meters dominate. Milwaukee has a very basic model that's only $140.