I've never used March pumps myself, but they've been around for a couple of decades. They never really became popular for aquarium use probably because they are relatively expensive (with no advantage I've heard) and they were poorly marketed to hobbyists. Is there a reason you're considering March? I'd look into Ampmasters and Sequence pumps for something in that neighborhood.
Only reason for the March is I can get one now used, only a few years old, for about $65USD. Figure if it calves, not a big deal only $65, but if they're junk no sense in throwing away my money either. Also, eventually will be getting the Iwaki MD-100 so thinking the March might not be a bad to have around as a spare.
It's the 6 series so at a 20' head it's rated 1900gpm plus.
