These will pump just fine through 1/2" ID hose.
I was thinking of trying to see if one of my my 5 gpm Delavan pumps could be adjusted to run through the 1/2" hose as a backup? { One quick try so far and it was cycling on and off-shuddering etc }
Before I go through all the trouble of trying, I thought I would see what you all have to say about that.