is anyone using one of these external pond pumps?

is anyone using one of these external pond pumps?
1/2 HP ELECTRIC CLEAR WATER PUMP - POOL/POND/FARM
http://cgi.ebay.com/ws/eBayISAPI.dll...1310 643&rd=1

Mine is not working now and I need to get another one pretty soon.
Currently I have: 1/2 HP Submersible Dirty Water Pump ponds farm floods
http://cgi.ebay.com/ws/eBayISAPI.dll...1375 607&rd=1

This is the second one of these I have and I'm done with them. This one
is doing the same thing that my first one did. It blew the circuit on
the gfci outlet. I reset it and it runs for a few min and the circuit
blows again. Its not the outlet because anythig else plugged in still
stays running.

Anyways at my office we have a 300 gallong salt water aquarium and this
is the kind of pump we use there and it runs 24/7 and its been ruinning
for over 2 years straight with no break downs. The only difference will
be that if I get one mine will have to live outside. I will probably
make some kind of cover for it.

Thanks,
Chris