Get an old wire coat hanger and unwind it to a single straight piece of wire 
and poke it up the pipe.
Or drop the tank and invert it while shaking vigoursly.
Others may have better ideas.
Check the pipe from the tank to the pump or pump inlet is not clogged.
Others may have better ideas than these.
Daniel1312
In a message dated 29/09/00 23:21:22 GMT Daylight Time, 
stephenlease@yahoo.com writes:
<<  So I unscrewed the
 line at the tank.  This did me little good because
 there is more piping inside the tank. >>
 
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