Colleen, I have 1.25" water line, and a 4200 gph pump that was running about 20' of water line to the Skippy filter. For some reason, the pump kept quitting. I figured it was the water in the line froze, as it was above ground on the outside edge of the waterfall ground area. Maybe it was something totally different, but never had a problem with the pump running before, and it did it each and every time the temps plummeted below freezing for day and night for more than a day. So, we shall see if the insulation will help keep them from freezing. Plus, the lines will be more underground in a sense, and that may help, too. I'll be shutting down the tee'd line to the fountain for the winter, so it should push water only through the Skippy. Also, I don't even use a filter for that pump, never have. It is strong enough to push pretty good sized stuff through it, so I see no need to put a filter on it. It's up off the bottom of the pond, about 16" so the only thing that runs through it is the water for the most part. There is some plant stems on the outside of the cage right now, but other than that, it doesn't get clogged.
The pump I used to push water in a fountain type thing for the goldfish pond kept getting clogged because I had the filter in the cage. Once I removed it, it never quit. That one is also up off the bottom, in the pond, and no reason for it to get clogged, as the water got into the pump and just straight out and up to the surface, causing a bubbling effect.
