Can you add a "back wash" hose to the filter and divert the water to a more desirable location (lawn?). This one is $15 at my local Wal-Mart. Harbor freight has them also. You normally need a hose clamp also.
Late edit: I just noticed, this comes with a hose clamp.
http://www.walmart.com/ip/HTH-50-Pool-Backwash-Hose/20703032
Late edit: I just noticed, this comes with a hose clamp.

http://www.walmart.com/ip/HTH-50-Pool-Backwash-Hose/20703032