Sonosailor admits
"...I have gone through 4 pumps in two short Canadian seasons..."
Perhaps you should reflect on Einstein's definition of insanity:
"Doing the same things over and over - and expecting differing results" 
Now, I generally like Flojet products, but I've not used the "Quad Bypass".
Inb my ignorance of this specific product, I'd suggest that it's time to try something else.
Gord