I also seem to have a lot of slimy algae in my pond this spring, and as soon as the ice melted it grew a dense mass of free-floating algae.

But I don't run a heater in the winter, not even the filter pump, just a bubbler once it gets frosty.

I don't think it would be the deicer. Perhaps the snow helped insulate the pond. Is it possible that the pond recieved some nutrient rich run off when the snow melted?

No, no run off. And we seemed to go for months at a time without much sun. I just don't get it.

I think this year was just a bad year for algae because my pond was really bad in the stream,all around the rocks inside and by my skimmer. I cleaned my stream with Ecoblast a few days ago but will have to wait until the water warms up for the inside :( Have had my pond for 4 years and this is the worst.

At least twice before I really got after it, it stopped my small pump. When I started my large pump and falls I had to clean my pre-filter about every 15 minutes to keep it free. Needless to say, I ran it only when I was in the yard where I could watch. Gradually doing a lot better now. I have been netting it out and cleaning leaves out of the pond as much as possible.