Very sorry to read about your experience - temporarily takes some of the fun out it. I have a similar setup with my 180 and recently setup a remote sump (about a 30' run) powered by an Iwaki 70 and "assumed" the extra 100 gallons would minimize any downtime problems. How big was your sump? Also, I ran 5 separate GFI lines from the fuse box to the fish tanks because I had an occasional GFI trip (power surge?) for no apparent reason. No problems since then. I tried to balance the load to keep water moving if one tripped, however, I see no way around the Iwai 70 going down short of putting in a second return pump. Two smaller pumps might be a good idea if the big pump ever quites. Do you know if a remote sump pump really needs to be on a GFI circuit?
Please post any solution you find, as I am sure others are in ,or might be, the same situation.
Best regards,
Dennis