I use the "nano con dientes" (with teeth) on my 29.  I like it, but as SFork says, it can be a little noise if you're running it near it's limit.
	
	FYI, if you're looking at the nano, I run a Mag 3, but have it teed to feed my TLF 150 reactor, so it's not sending its full flow up back into the tank and it's still a little on the higher end for flow.
	
	Not sure if Gresham meant silicone sealant or grease.  I used a little silicone grease (plumbers) on the gaskets.  It comes with an elbow drilled with a hole for an air tube.  In restrospect, I might have considered replacing it with a T fitting.  I think it might have allowed more adjustment of the air and quieted it down a little.
	
	Also, not trying to scare you with the noise.  It's not super loud, you can just hear some water running.