Hi, I have a 25-30 foot galvanized steel gutter run with downspouts on
each end. There is a slight dip in the middle so water collects there
and never drains. I've cleaned out any mud/debris and still I get
about 1/2 of water that can't drain. How can I fix this? I'm pretty
handy but never addressed this type of problem. Looking for advice,
tips, lessons learned, etc. Thanks.

The gutter and roof are about 5-6 years old.