i have heard a lot of good things on this site about sequence pumps so i found one that might work it is the Sequence 750 4200SEQ12 it uses 160 Watts but should give a flow at 3 ft of head of about 3500GPH in stead of the 2000GPH i was planning with the submersible pump. i found a 6" Strainer/priming pot with 2in inlet and output that would go inline from the BD to the pump and so i wouldn't have to worry to much about larger things going thru the pump. so it would go BD => 6" Strainer/priming pot => sequence 750 4200GPH pump => 150GL stock tank filter. that would bring my retention time in the filter down from 4.5min to 2.5 min. is that enough?