I have submersibles, the con of a non-sub can be if it hums louder than the
waterfall, submersibles, being under water are silent. My waterfall could
probably cover the hum, but in my filter situation a submersible has worked
fine. ~ jan

See my ponds and filter design:
http://users.owt.com/jjspond/

~Keep 'em Wet!~
Tri-Cities WA Zone 7a
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