On 21 Oct 2006 09:47:25 -0700, wrote:

The lowest fin forms a seal, so there should be no way for anything to
get back up between the fins.

"should" being the operative word. If one fin is good enough why are
there four or so? It doesn't take a very big gap for muck to get through
and build up over the years.

--
Cheers
Dave. pam is missing e-mail