Is there a consensus on the type of pumps one should use for waterfalls and streams? I may need a high capacity pump for a stream and waterfall feature and it looks like I'm right at the threshold of external pump instead of a submersible style pumps. Does one design use less electricity over another? If I'm going to be running the pump 24/7, what is the general recommendation? If I need high lift, say 37 feet including a long stream and need 7000 gph, does one design work better than another? I guess I don't see too many forum topics discussing the various types of pump products for varying results needed.