I bought this pump for my 500g. My sumps, filters and skimmer are in my basement. There is about 20' of horizontal run, and 10-12' vertical head pressure. This pump performs really well. I can neither confirm nor deny the seller's assertion about the efficiency of the pump, but it is quiet, and even with all that head pressure moves a lot of water. I just wish I bought the 11,000 gph pump instead! But for those of you looking for an alternative to some of the sequence pumps, these come very highly recommended.
http://cgi.ebay.com/MAXIFALLS-water...=190503714900&ps=63&clkid=8753879277158567492
http://cgi.ebay.com/SUPERFALLS-11-0...468?pt=LH_DefaultDomain_0&hash=item3cb7657d2c
http://cgi.ebay.com/MAXIFALLS-water...=190503714900&ps=63&clkid=8753879277158567492
http://cgi.ebay.com/SUPERFALLS-11-0...468?pt=LH_DefaultDomain_0&hash=item3cb7657d2c