Place the 100 watt de-icer in the garbage, or see if you can get your money back! If it's the de-icer I am thinking of, a small pump attached to a round foam disc, run get your money back, does not work for our weather, maybe good to -15 at the most, and then it freezes.
My pond circulates all winter with the main pumps that are in the water, filter on shelf where I can get to it easy. There is lots of oxygen in my pond because there is always open holes in the ice where the water pours from one pond to another. My pond does not freeze solid, cause there is the 1500 watt heater that I use when the temperature is below minus 10c. The water will not freeze in the hose of the pump if it is always running, faster than 100 gph. I recommend you use a least one pump of at least 2000 gph for your size pond, for winter use. I run at least 4000 gph between the two pumps, (underwater) with good filters so they don't get plugged, last thing you need to do is clean filter when it is minus 40!! I much rather use my pumps than a air stone bubbler. This way the water is still filtered all winter long. I know lots of people who killed their fish in this weather relying on "bubblers" maybe some people can make it work here, but I don't know of any. Wayne from Edmonton has a big bubble that he says he is going to use this winter... with a HEATER, not alone cause it is too cold here.
I like your pickeral weed, looks really nice and you have good luck with it, I tried it once many years ago and it did not do well for me. The plant that does very well for me is the Yellow flag water iris. It grows very very tall for me, over six feet tall. I used to have it planted in basket in pond mud that I made, and it grew so big it bust out of the basket over 20 years ago. There is no soil left, and I have divided it many times over the years, now it is so large I fear I can no longer move it!! So I cut around the edges and give lots of chunks away. The plant floats now, like a big boat, I could float it to the other side if I wanted. It is so big, it never falls over, somehow it is just floating, and the fish swim under it!! It took years to get a massive clump that is this large. It used to be much smaller, and I just wedged it to the side of the pond and used some rocks to hold it in place, many many years ago. Now it has grown way past the shelf and is floating in the middle of the pond in water three feet deep!! Not all irises will grow in water that deep, most irises are bog type plants that like shallow water. Did any of your irises bloom yellow, if so it is most likely the yellow flag.
When the snow falls on the pond I leave it. Snow is good over the ice, helps to keep the pond insulated. When the snow falls heavy over the ice, the holes in the ice seem to grow larger, as the heater can better heat the water with a "blanket of snow" over the ice.
I will post pictures of this when I get some ice on pond. No ice on pond yet, not using heater yet, not cold enough. I will post lots of pictures of how the water flows UNDER the ice in the "spill way" *spill way is where water flows from top pond into middle pond and down to bottom pond. Sort of like little water falls that connect each pond.
First Picture from (late spring) of two of the three connecting ponds and the large yellow flag takes quite a bit of room as you can see. Notice how large the hardy pond plants are in late spring. This is because the pond never shuts down so they get growing very early here, like in March the new shoots are popping up. Second picture is plants growth in april.... most people have not even considered getting their pond back up and running yet... the benefits of running your pond all winter .... last picture is in march
