Aerator and bottom heater?

[waynefrcan]

Nah, that statement means death below 40F. That's ok it's a view shared by most USA ponders, but it's still wrong.

 

[crsublette]

In all english it reads the same stating, "which is very nearly the coldest to survive". Context is important. Also, the density of the water is extremely important as well in dictating what is safes since, here in the states, the east and west coast water has a higher salinity than the central region. Now see, they're all about the health of koi and not about appearances of the fish just simply being alive. Believe whatever you want, but i'll definitely argue when it comes down to pushing bad information. If I'm wrong, show me something better than personal anecdotes of "my fish lives even after being just about, almost nearly frozen".

Water density. Water density indicates the weight of water and also when ice crystals begin to form. Density varies across all regions due to various contaminants. From what I understand, the density dictates when the water actually starts forming ice crystals. So, lets use the MPKS article that states the water's maximum density of 39*F; this mean the water will start forming ice crystals to eventually turn the water into slush. However, residual heat must dissipate before this can happen so this is why you just don't instantly see your entire pond turn into slush even though it might be 35*F.

I still do not understand how lowering the maximum density hurts fish. I thought it was simply the water temperature. My guess is the water's extra weight forms too much pressure that the fish can bare.

That's ok it's a view shared by most USA ponders, but it's still wrong.

There is a tremendous volume of bad information out there often pushed by people too apathetic or by people who just don't want to be told what to do. They want to do, what they want to do, whatever they want to do as long as they eventually get the same results. This is the entire reason pond product market is tremendously full of outdated, inefficient, and uneccesarily risky material since the market is using 20 something odd years old wisdom because the old stuff still sells. Breaking customer's bad habits, persuading them to progress, is the toughest thing to do for a business.

 

[waynefrcan]

IS this going to be another "I'm smarter then you" topic?

Very nearly Is meant to say 38,39 F, Not the 32.7 we know they survive in.

 

[crsublette]

From what i've read, only reason "you know they survive in 32.7*F water" is because you simply just see them alive and moving and this means to you they're happy. That's fine, but there are readers who are looking for more; if not interested, then just ignore my posts.

Nope, not smarter than anyone. Just hoping to help. The attitude does not help anyone. On that note, I'll leave ya with that unless there is something I believe I can add to help the reader and good luck to ya in your ponding endeavers.

 

[waynefrcan]

Gosh, no read the Pondtrade link I provided in this topic. Also my local expert and his customers here in frozen Canada has successfully wintered fish at this temp.

 

[crsublette]

Yep, everyone has their local experts. In attempt to clarify the article for the reader, it makes many assumptions that are flat out controversial and some of it just a bit odd, raising a few flags to me.

1. Anoxic zones contributing to fish kills ((fish know where to get their oxygen, they don't stay in the anoxic zones)).
2. Air diffusors water current is very limited, so what he calls "dead zones" will still be created, and the bubble surface area does not transfer as much O2 into the water as ya think, it transfers just enough. Most of the O2 recharge occurs when the bottom water pushed to the top where it can be exposed to the atmospheric pressure at the water surface area, except you don't need to do that during winter since the cold water holds tremendously more O2 and its easier to recharge.
3. Your pond design does not have to be devoid of convolutions if you know how to properly manage water currents.
4. He even points out the dangers of salinity affecting the freezing point, which is a bit odd for him to mention this since he says "very close to or just above 32*F water" is perfectly fine, healthy for the fish.
5. Organic decomposition significantly decreases in cold waters so this is why only a small hole is more than enough to allow gasses to expel. First of all, good pond husbandry dicates keeping the pond mostly clean of organic debris; Colleen's pond is actually full of organic debris due to the soil she uses and plants that overwinter and you like to hold her up as an example, which is fine to me, but it is in conflict with the article's author.
6. Air diffusors pumping cold air will reduce the water temperature through heat displacement, yet the only reason he gives for doing it is that his buddy does it so it's good enough for him.
7. He says that "Adding aeration lowers a pond’s water temperature more quickly than without, but the temperature does not go any lower than what it would have been anyway," and that's apparently not a big deal to him since he simply just "sees them alive, moving, and this must mean they're in optimal healthy conditioning and happy".
8. "Some may think that a water pump placed in the center of the pond with the outlet shooting straight up will provide the same benefit. Yes, it will until the intake of the pump plugs or it domes over. In this dome situation the pond surface is sealed off from the atmosphere and there would be no O2 exchange." This can occur with aeration as well as Dave posted previously. It is the heat and moving water in combination that prevents ice from forming.

The Pond Trade article ya mentioned is good for beginners and I read articles like that quite a bit, but it lacks detail, which is fine, since he probably did not want the article to be too long.

 

[Craig58]

Water density. Water density indicates the weight of water and also when ice crystals begin to form. Density varies across all regions due to various contaminants. From what I understand, the density dictates when the water actually starts forming ice crystals. So, lets use the MPKS article that states the water's maximum density of 39*F; this mean the water will start forming ice crystals to eventually turn the water into slush. However, residual heat must dissipate before this can happen so this is why you just don't instantly see your entire pond turn into slush even though it might be 35*F.

I still do not understand how lowering the maximum density hurts fish. I thought it was simply the water temperature. My guess is the water's extra weight forms too much pressure that the fish can bare.

I think the concept of this 39F number is the problem. This it simply the temperature at which the stratification flips in either direction. Not when ice crystals form. Yes, the composition of the water can cause minute differences in this but doubtful if that will cause more than a 1 degree shift either way. High salt of course, but that would have to be ponds that actually add salt.

Water at 38 is more dense than water at 37 so the 38 degree water "sinks" if you will with the 37F water above it. 36F above that, 35F above that, etc.. until you hit 32F at the surface. The 38-39F water is on the bottom.

But if all the water is above 39 degrees, then 40 degree water is less dense than 39 and the 40 degree water rises. 41 degree water rises more.. etc....

In the winter, as long as the surface water remains below 39F, stratification can happen. With 32 degree water at the surface and 39 degree water on the bottom.

I don't know if you can realistically expect to see anything above 39F on the bottom of a pond. Since if the bottom temperature hits 40F, it will become less dense than the 39F water and begin to travel upwards until it cools. This convection alone should be enough to cause some movement in the water and fresh O2 to an area.

So I think the only way you can get 40-45F on the bottom is with heat from the ground or a low powered heater. If the heater was too strong on the bottom, the warm water would push all the way to the top and cause excessive mixing which in most cases would overwhelm most heaters and you'd basically have a 33F pond throughout most if it with a column of heated water which isn't going to do much for the fish sitting on the bottom.

But I think a very low powered heater on the bottom might do the job. So when the heated 45 degree water rises, it quickly cools to 39 within a foot or two, before reaching the top and preserves the colder stratified layers above it. I.e. a little added heat might hold a section of the bottom around 45F, but a lot of heat will actually cool the pond down to 33F.

No idea if this is the case.. just trying to think about how the science works.

They use to have heating wires that lay in gutters to keep them from icing. They are low powered, waterproof, temperature controlled and fairly cheap to run. I wonder how a loosely coiled section of this sitting on the pond bottom would work? But they might not come on until 33F. Might need to find something with some type of adjustable thermostat.

Craig

 

[crsublette]

Good explanation Craig. Good stuff.

Yeah, those OSU articles I linked talks about all that. Also, talks about how O2 stratisfys as well when the water is completely iced over. I don't know if I would want to completely rely on convection alone to provide enough O2; I suppose it depends on your BOD (biological oxygen demand) since it is different for everyone.

I think the concept of this 39F number is the problem. This it simply the temperature at which the stratification flips in either direction. Not when ice crystals form. Yes, the composition of the water can cause minute differences in this but doubtful if that will cause more than a 1 degree shift either way. High salt of course, but that would have to be ponds that actually add salt.

Water - The maximum density of water occurs at 3.98 °C (39.16 °F)

Ice crystals only start to form when the heat, through enthalpy, dissipates. The freezing point changes with the density therefore changes the enthalpy. Correct? ((trying to understand this, seriously asking here))

I'm told that is salt is introduced to lower the freezing point, therefore density, so that ice can become much colder than it actually is. Now, how much salt does it actually take? I was told anything over .2 mg/L. I can be completely wrong and would love to read something that gives a detailed explanation on it if you have one handy; technical stuff don't scare me, I truely enjoy it.

 

[crsublette]

So I think the only way you can get 40-45F on the bottom is with heat from the ground or a low powered heater. If the heater was too strong on the bottom, the warm water would push all the way to the top and cause excessive mixing which in most cases would overwhelm most heaters and you'd basically have a 33F pond throughout most if it with a column of heated water which isn't going to do much for the fish sitting on the bottom.

Ya sure the warm water doesn't go outside the column just above the water??

I put my heaters under my waterfall and one in my skimmer which feeds some fountains. Back in Winter of 2011, the entire surface area of my small watergarden (about a 9 foot by 9 foot oval) did not have an ice cover until the temperatures dropped below 15*F, staying there for a good half of the day; even then, there was almost a 2 foot radius around my heater where there was not any ice and the ice that did form was quite thin. And then, my electricity went out; oh man, then that ice got about 4 inches thick over everything. I imagine my water temperature didn't fluctuate much since I already had a nice thin layer of ice on type; after electricity went out, the water at the top layer just must've reaching maximum enthalpy causing the ice to be 4 inches thick and insulate the water below. My water must've been at least below 35*F.

I'm not talking about heating a pond for the fish. That's crazy town expensive; however, I have read a fella on this forum showing how he creating a simple makeshift greenhouse structure over his pond that kept it nearly 50*F. I'm just gonna have to roll with the punches and hope for the best, but I'm not gonna lie to my self saying its a healthy thing to do if I had a choice in the matter. Still good to know the stuff.

 

[crsublette]

Same author of that Pond Trade article also wrote another article, Pond Aeration Placement During Winter, the author states, "If you start heavy aeration after the ice is already formed then you can possibly super cool a pond. The temperature can go from a relatively balmy 39°F to 32°F in a few minutes. This is pure conjecture on my part because I do not want to do this and jeopardize my fish or any of my clients’ fish." Don't get me wrong. He still recommends aeration. The point he is making that you need to start doing the aeration the moment the water starts to cool and not after it has a thick layer of ice over it.

It truely is a fine line the author is walking in telling readers that 32.1*F or 32.00001*F is no problem. Well, I guess the good thing is that they're not completely frozen!! heh

 

[Craig58]

Ya sure the warm water doesn't go outside the column just above the water??

Yep. pretty sure. Unless you have outside currents that change the flow of water, any water heated above 40F will try to rise. No different than a fire in a fireplace, (or building!), or hot winds. Hot winds rise, cold sink.

Don't get me wrong, sure, there is a little area around the heater that will be warmer but in the kind of cold we are talking about, I'd say once you get an inch or two away from the heater, any warm water will be moving upward. It might spread out some while rising but that would just dilute it and cool it faster. Once it's cooled to 39, it won't rise any more but spread out like a mushroom cloud. The rising warmer water will cause water to be pulled from the side around the heater and into the heater and up the column.

Craig

 

[callingcolleen1]

Charles, please don't get upset.. but what do you know about wintering fish in minus 45-55 c temperatures anyway.... never thought it got that cold way way down in Texas!! I on the other hand can tell you my fish have stayed outside here in Canada for over 20 years now in some of the coldest temperatures found on planet earth, and have first hand knowledge of wintering fish!!

My koi are very healthy, they would have to be according to the experts.... just to survive in this harsh climate, and some of them are over 20 years old now, and they eat DOG FOOD too!!!
(That must be why they do so well in Canada, my superior diet of Dog Food, and I'm sure the experts would have something to say about that too!!! Ha ha ha

I think the experts are all from Texas too and can't see how we even survive in this part of the world!! They probally think you need to take a team of huskys from the Canadian border and that we all must live in igloo's! Ha ha ha.

 

[callingcolleen1]

Yes it is possible to have to much circulation and super cool the fish, this is very true Charles. Although if you have a 1500 watt heater, not too much to worry about then, except the power going out!

 

[callingcolleen1]

Yep. pretty sure. Unless you have outside currents that change the flow of water, any water heated above 40F will try to rise. No different than a fire in a fireplace, (or building!), or hot winds. Hot winds rise, cold sink.

Don't get me wrong, sure, there is a little area around the heater that will be warmer but in the kind of cold we are talking about, I'd say once you get an inch or two away from the heater, any warm water will be moving upward. It might spread out some while rising but that would just dilute it and cool it faster. Once it's cooled to 39, it won't rise any more but spread out like a mushroom cloud. The rising warmer water will cause water to be pulled from the side around the heater and into the heater and up the column.

Craig

Just so some people don't get confused, hot air will raise, and cool air will sink.... in water, warm water will sink and very cold water will raise, that is why ice forms at the top of water first and not the botton.

 

[crsublette]

Colleen, you can't upset me. Ya have too good of a humor. Believe it or not, I like you ((in a totally not creepy way))

ya'll's winters amaze me. Concept of ice insulating the water doesn't change, just the depth does. I know my dinky little watergarden would definitely not work up there.

Im an all weather cat. Winters used to be much worse when I was a kid where it was an actual zone 6 winter. Zone 2/3 sounds to be very interesting experience; it'll give me a chance to really test out my long underway.