ummgood,
I have scanned this thread but not read it thoroughly.
Can you hook up a backwash hose to your gutters? An inch of rain can easily turn into 3" of fill for your pool if you have enough gutter volume.
I probably could but the problem is my house has a very radical roof design and I have a ton of down spouts. Plus I would think my gutters aren't that clean so I would be paranoid about getting junk in my pool.