Winter and water tempreture control measures

[WayneB]

Hi All

We are now moving into winter and im preparing my pond for winter, there are a few things that i would like answers on.

As i said before our winters in Cape town does not get very cold but I am still trying to maintain the "warm" tempretures for as long as possible. Our winter tempretures averages at around 16'C. My pond is currently sitting at 20.7'C. The air tempreture outside today is 19.8'C

Every evening and on cold days i have gone out and changed the circulation of my pond so that it suck the majority of the water from the skimmer and very little from the bottom drain (Maybe 1/4 and 3/4 from skimmer), most of the water also gets returned via under water returns 30cm below water level, the water fall is turned to run at a very slow trickle. This is done to try and prevent the water from being chilled and to create a warmer area at the bottom. So far i a think that it is working but am i not maybe fooling myself?

The pond contains 32 000 liters of water and is build at ground level with a short 30cm high wall / edging around the pond to prevent most of the debris from blowing onto the water, the deepest part of the pond 2.9m and the shallowest part 1.5m. There is no heater on the pond.

What i have noticed is at night time when i go out at 22:00 to put my koi to bed that there is steam (lack of a better word) coming from the surface from my pond....huh. whats that?

Now these are my statements / questions; Are they Myth or truth.

1. Tempretures in the deepest parts of the pond is warmer than the surface during winter.

2. Returning water under water level will maintain the warm water tempreture for longer.

3. Returing water via the water fall \ bakki shower \ trickle tower will chill the water to the same tempreture as the air.

4. Will air diffusers chill water?

5. Will sucking from the skimmer instead of the bottom drain help to maintain a warmer water tempreture in the deep ends of the pond.

Can i please have your thoughts and any advise aswell.

Wayne

[MCA]

Quote: Now these are my statements / questions; Are they Myth or truth. 1. Tempretures in the deepest parts of the pond is warmer than the surface during winter.

MCA: depends on depth of pond, amount of water movement between floor and surface. In our 8" pond there is no difference as the air domes and TPRs and shower returns keep all the water mixing. If you have stratification of water....not enough current for koi.

Quote: 2. Returning water under water level will maintain the warm water tempreture for longer.

MCA: very likely. But the best way to keep in the heat is to cover the pond surface to keep off "wind chill".

Quote: 3. Returing water via the water fall \ bakki shower \ trickle tower will chill the water to the same tempreture as the air.

MCA: Definitely not true. If it were when I ran our two showers in 20F air temps the showers would have been big blocks of ice. They were not.

Quote: 4. Will air diffusers chill water?

MCA: No. The air pumps cool themselves via the pumped air. So the pumped air is slight warmer than surround air. So take advantage of that warmer air by putting a clear pool cover (like heavy duty bubble wrap) over the pond...or floating on the surface of the pond. If it floats on the surface, you like need to bypass waterfalls/weirs that feed the pond.

Quote: 5. Will sucking from the skimmer instead of the bottom drain help to maintain a warmer water tempreture in the deep ends of the pond.

MCA: and how will skimmers help remove any organic material (fish poop) in the pond floor? Run you pond as in summer. Just put a cover over the surface to reduce wind chill. Bypass any waterfall/weir as needed. Also you can turn off showers if you already have enough filtraiton...and the chilling effect is too great. And last but not least, consider active heating by gas, electric, or solar devices.

[JasPR]

it's about wind chill at the surface and not the idea that layers or zones of warmth exist in your pond and should not be disturbed ( that is a myth that comes from observations of natural lakes and ponds with leaf decay, thermoclimes and depth vs surface realities of wild ponds and lakes. But ice formation and totally still water are not the same as koi ponds are). Turn over and surface disruption all contribute to heat loose into the colder winter atmosphere. And wind chill is public enemy number 1. If you think in those terms, you will identify what to do in your personal circumstance/settings. It is a VERY good idea and highly recommended that you build a cover for your pond if you are concerned about temperatures going below 45 F. JR

[WayneB]

Thanks guys for helping me sort out myths from facts.

So going forward i will suck from bottom drain and skimmer as usual without restricting one or the other and return the water via under water returns. Water fall will be set to a very slow flow to help maintain water temp.

I can handle this.

Thanks