Pond Contraptions: What are they, and do they really serve a useful purpose?

[cas]

@Meyer Jordan does this help explain? Without the air stones I don't believe the water at the bottom of the pond was being circulated.

 

[Meyer Jordan]

@Meyer Jordan does this help explain? Without the air stones I don't believe the water at the bottom of the pond was being circulated.

View attachment 87924

Sent you a PM.

 

[adavisus]

I don't see lighting as a feature on the list :::gulp::: its the only gizmo I do use :::doh:::

 

[Mike in Vermont]

Oh sure, there are many ponds I've seen that just pump their water through spitters or fountains and don't have waterfalls. I also listed Pressure filters separate from bio and mechanical filters although pressure filters usually try to include both, but as far as I'm concerned I don't think they do either particularly well.

Lets talk about aerators a little more. You mentioned in the other thread that "If a pond is large enough to where the wind fetch is sufficient, then no, aeration is not needed." I beg to differ on that general statement because of all the pond contraptions on the list above, aerators are the only contraption that I've ever seen used in natural lakes. In fact the closest lake to where I live (5 miles away) has an aerator running right now. Yellow Lake And there is another lake about 10 miles away that also runs an aerator in the winter. The reason being is that these lakes have often suffered heavy fish die-off in the winter without the aerators. So if aerators are frequently needed on these large bodies of how much more important might they be in our little backyard ponds that generally have a much higher fish load?

A paper on the subject with information aeration with some info specifically about Yellow lake

I found this interesting. Strange how thousands of fish died, from initially turning the diffuser on. I'm guessing it would take weeks to get the water circulating in a lake.
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I'm not sure if they mentioned this but, it's important not to place the diffuser in the deepest part of the pond/lake. I guess it wouldn't matter in the winter but, the colder water is needed for the trout in the summer. For example, if a pond is 15 feet deep, the diffuser should be placed at a depth of 10 to 12 feet.

 

[Mucky_Waters]

Perhaps Meyers, the limnologists and the science community need to get out swimming more.
When my boys were young we had an above ground 5 ft deep swimming pool that we would cover and turn the pump off when not in use. It had a floating thermometer and some days after work I'd go for a swim remove the cover and look at the thermometer and see a temp of 30 C and expect the water to be quite warm, but after jumping in it was actually quite cold (and refreshing I might add). So what was going on? After several swims like that I realized that without the pump on a very obvious thermocline was developing on a micro scale. The top surface had a layer around a foot deep of very warm water and by just extending my arm down a couple feet or so you could feel a radical change in temperature and by diving down to the bottom you could tell that the bottom few feet had a much less radical change, but obviously cooler temperatures. In this case the "thermocline" layer was only about 1 ft thick. Now I never actually bothered to place a thermometer on the bottom of the pool, or take readings to find out what the temperature was exactly at the different depths, but simply by feel I was able to tell the change in temperature at the different levels and it felt exactly like the diagram Meyer's posted, except the low temperature did not get down as low as 4 C and it was on a much smaller scale. Of course there is no depth scale on the graph that Meyers posted.

As for Mitch's question about my pond, normally with my pumps running I won't see any difference between the top and bottom, and in the winter when the pond is frozen over and no pumps or aerators were going, I have read a difference similar to what you have experienced, little more then a couple deg Celsius, but that was a flipped temperature with about 4 C at the very bottom and around 2 C just under the ice layer. I always run a pump in the winter now so the temps are more consistent now.
However on one occasion in the summer my GFI circuit blew on my pumps and I didn't notice for I'm not sure how long. And I did have a top and bottom thermometer in my pond at the time and saw that 5 deg difference, which was probably a lot less than the temperature difference I experienced in the swimming pool.. And no I didn't measure the layers or get in and swim to see if if felt exactly like the swimming pool, but it was obvious there was some stratification going on.

 

[Mucky_Waters]

I found this interesting. Strange how thousands of fish died, from initially turning the diffuser on. I'm guessing it would take weeks to get the water circulating in a lake.
.
I'm not sure if they mentioned this but, it's important not to place the diffuser in the deepest part of the pond/lake. I guess it wouldn't matter in the winter but, the colder water is needed for the trout in the summer. For example, if a pond is 15 feet deep, the diffuser should be placed at a depth of 10 to 12 feet.

I've noticed that they turn on the aerators much earlier in the year now, perhaps that's why.

 

[Meyer Jordan]

Here is a little 'light' reading on thermocline depth.
https://www.google.com/url?sa=t&rct...1ZuZQ3cUnVHjJD1dQ&sig2=8kr-g6TBkK_G1MPdvt6I1w

 

[Meyer Jordan]

Perhaps Meyers, the limnologists and the science community need to get out swimming more.

What you are describing as a thermocline is not a thermocline in the scientific sense.
http://www.thefreedictionary.com/thermocline

 

[Mucky_Waters]

There are several different definitions there, I only see one that might not apply.

 

[Meyer Jordan]

What these concise definitions do not say is that a thermocline is further identified as being a layer of temperature differential that prevents the mixing of the water layers above and below this line. In addition, in stratified bodies of water the layer below the thermocline is typically anoxic because of this barrier to the mixing of layers.

 

[Mike in Vermont]

Can thermoclines be permanent in large bodies of water?

 

[Meyer Jordan]

Can thermoclines be permanent in large bodies of water?

Yes, under certain conditions..... mainly geographic location.

 

[morewater]

Want to see how it inverts? Go fishing in a larger body of water during "turnover".

 

[Mucky_Waters]

What these concise definitions do not say is that a thermocline is further identified as being a layer of temperature differential that prevents the mixing of the water layers above and below this line. In addition, in stratified bodies of water the layer below the thermocline is typically anoxic because of this barrier to the mixing of layers.

Meyers I think you are reaching for straws here to try and put a very specific definition on a thermocline that doesn't exist. The link you yourself sent shows that there are various definitions of what a thermocline is. Just because there haven't been a lot of scientific papers written and published on thermoclines in swimming pools, doesn't mean they don't exist.

 

[Meyer Jordan]

Not reaching for straws at all, just trying to clarify a definition for someone who obviously is unwilling to accept scientific fact even when they read it.. Take the time to do the research and maybe the fog will lift.
In swimming pools over 5 feet in depth, it is possible for a thermocline to form.