Recommendations on pond pumps?

[carolinaguy]

Thanks, Actually my pond exactly 18 inches deep. Wold you reccomend placing it at the bottom or top. Im working in a system to circulate only the top water.

since we don't feed and add nutrients to the pond below 50 degrees, the issue of dissolved organics should not be a problem. because a nitrogen cycle process is inactive in the winter, sleeping bacteria, no waste material, and no ammonia build up, the water column should be homogeneous top to bottom chemically with only a temperature variance. if you had a 3 to 6 foot deep pond, the temperature gradient could be as much as 3 degrees with warmer water at the bottom. the bottom water gets heated by the surrounding earth and rock which is a giant heat sink, and of course 38 degree water is the most dense and sinks to the bottom. koi do better with water at 35 degrees or higher, so we circulate top water only, shutting down the bottom drains almost entirely,with the skimmer as the primary intake. with an 18 inch deep pond, i'd still circulate top water only to keep the bottom fairly undisturbed and retaining as much heat as possible. now we have an airstone in ours to create a small vertical stir and ensure plenty of dissolved oxygen down low. that air column is turned down to its minimum, and we look for koi behavior like surfacing and piping as our measure of good oxygenation down low. we never see them at the top in the winter, and our pond is 39 inches deep at the lowest point.

 

[Pondmaster]

Are you saying that you have stratification in 39" of water with an airstone running? You would be surprised at just how much current an airstone creates.You will probably find no measurable difference in the temperature from top to bottom. If you have a lot of decaying material on the bottom of the pond, you could make the bottom temps a little higher,but that's not good. It takes fairly deep water for any stratification to occur.

Then why does the surface freeze first? It is exposed to the cold air and ice floats.

 

[j.w]

My pump is not on during the winter when it sits on the bottom of the pond. I just keep it in there cuz it needs to be in water to stay conditioned so it doesn't dry up inside. I have a small air stone that bubbles up and I have two fountains in there that just have a solid flow of water coming up which also helps to keep holes in the ice if we get a cold spell. Where I live we don't have long periods of freezing weather so I never have any problems so far. I have cleaned out the muck on the bottom of the pond and clipped all the old lily pads off and done a partial water change and all is looking good for the long winter. The fish hang out down below where the temps are a bit warmer and don't receive anymore food til Spring and the temps go above 50 or so. This is my plan and it's working for me. Now if I can just keep the Heron away life will be good for the fishes

 

[DoDad]

You can still get the Sequence 4200SEQ12 and the 3600SEQ12 for less than $280.

 

[carolinaguy]

Are you saying that you have stratification in 39" of water with an airstone running? You would be surprised at just how much current an airstone creates.You will probably find no measurable difference in the temperature from top to bottom. If you have a lot of decaying material on the bottom of the pond, you could make the bottom temps a little higher,but that's not good. It takes fairly deep water for any stratification to occur.

Then why does the surface freeze first? It is exposed to the cold air and ice floats.

i'm getting about one degree fahrenheit top to bottom. one of our ponds in the club is 6 to 8 feet deep and gets more of a differential. remember that the ground around the pond is a giant heating element made of rock and soil with a higher temperature than the surface. that's why local building codes can stop at three feet recommended depths in climates that get to 20 degrees fahrenheit at the surface for weeks, and yet the water under the foundation doesn't freeze and cause frost heaves that damage the construction. the temperature differential can be attributed to radiant heat coming in from the sidewalls.

as for the cost of sequence pumps, we use webbs online and they even have an mdm line being manufactured for them exclusively. the prices don't appear to be that good anymore, and my number includes the pot and switch.

we keep the bubble stream very light so the stir is just enough to oxygenate but not to disturb the bottom.